# Phase 3 Task List — Merchant Analytics Dashboard

- Status: Approved — Phase 4 implementation authorized 2026-08-20
- SDD phase: 4 — Tasks approved and ready to execute
- Source plan: [`plan.md`](plan.md)
- Implementation authorization: Granted by user on 2026-08-20
- Approved by user: 2026-08-20
- Last updated: 2026-08-20

Tasks are ordered by dependency. Each implementation task must satisfy its acceptance criteria plus the Definition of Done in `tasks/plan.md`. Likely files are planning targets and may be adjusted before work begins, but a task must be split if it would exceed approximately five files or one focused session.

The user approved this task list and explicitly authorized Phase 4 implementation on 2026-08-20. Execute tasks in dependency order and stop at their named review checkpoints.

Commands named below are established by Task 4. Before then, verification uses the scaffold's generated commands and read-only contract checks.

## Phase A — Contract and executable foundation

## Task 1: Freeze the merchant API contract

**Description:** Confirm the provider-owned API specification and OpenAPI artifact are approved, versioned, and no longer marked draft before frontend transport code is generated.

**Acceptance criteria:**
- [ ] Backend `API-SPEC.md` and `openapi.yaml` identify an approved matching version.
- [ ] Approved CSV defaults, 90-day analytics/export audit retention, 30-day demo-authentication audit retention, opaque terminal reference, and stable Problem Details base URI are recorded by the provider.
- [ ] A checksum or immutable commit hash is recorded for frontend generation.

**Verification:**
- [ ] Validate OpenAPI 3.1 with the provider's contract command.
- [ ] Manually compare approved operations/schemas with `tasks/plan.md` Gate A.

**Dependencies:** None

**Files likely touched:** External backend contract artifacts; no frontend source files.

**Estimated scope:** XS — external gate

## Task 2: Freeze the static Nginx routing contract

**Description:** Obtain the deployment-owned rules for SPA deep-link fallback, immutable assets, `static/fonts`, and same-origin `/api/v1` HTTP/SSE/CSV proxy behavior.

**Acceptance criteria:**
- [ ] Deep-link fallback never intercepts `/api/v1` or static assets.
- [ ] SSE buffering/compression and CSV streaming headers follow the approved API contract.
- [ ] The target development and production origins are documented without frontend secrets.

**Verification:**
- [ ] Review the deployment contract against SvelteKit `adapter-static` fallback requirements.
- [ ] Record the approved deployment commit/reference in `tasks/plan.md`.

**Dependencies:** Task 1

**Files likely touched:** `tasks/plan.md`; external deployment artifacts.

**Estimated scope:** XS — external gate

## Task 3: Scaffold the pinned SvelteKit project

**Description:** Create the minimal SvelteKit 2/Svelte 5 strict-TypeScript project with npm, Tailwind CSS v4's Vite plugin, and the static adapter using current verified versions.

**Acceptance criteria:**
- [ ] Exact production/dev dependencies and Node/npm requirements are pinned in the lockfile/manifests.
- [ ] Tailwind's Vite plugin precedes SvelteKit and strict TypeScript extends generated SvelteKit config.
- [ ] No server endpoint, database dependency, secret, or placeholder auth token is introduced.

**Verification:**
- [ ] Run dependency install from the lockfile.
- [ ] Run the generated typecheck and production build.

**Dependencies:** Tasks 1–2

**Files likely touched:** `package.json`, `package-lock.json`, `svelte.config.js`, `vite.config.ts`, `tsconfig.json`

**Estimated scope:** M — 5 files

### Checkpoint A1 — Contract and scaffold

- [ ] Tasks 1–3 are complete and reviewed.
- [ ] No draft OpenAPI artifact is consumed by frontend code.
- [ ] The minimal project installs and builds reproducibly.

## Task 4: Establish frontend quality commands

**Description:** Configure deterministic formatting, linting, `svelte-check`, Vitest, and Playwright commands used by every later task.

**Acceptance criteria:**
- [ ] `format:check`, `lint`, `check`, `test:unit`, `test:e2e`, and `build` scripts are documented and executable.
- [ ] Unit/component tests use a browser-like environment appropriate for Svelte components.
- [ ] Playwright has desktop/mobile projects without embedding credentials.

**Verification:**
- [ ] Run every new command against the empty scaffold.
- [ ] Confirm a deliberately failing sample test/check fails, then remove it.

**Dependencies:** Task 3

**Files likely touched:** `package.json`, `eslint.config.js`, `.prettierrc`, `vitest.config.ts`, `playwright.config.ts`

**Estimated scope:** M — 5 files

## Task 5: Configure the static application root

**Description:** Establish the Persian RTL document root, route fallback settings, error boundary, and minimal auth/app route groups without feature UI.

**Acceptance criteria:**
- [ ] Root markup declares `lang="fa" dir="rtl"` and permits browser zoom.
- [ ] Static fallback and trailing-slash behavior match Task 2.
- [ ] `/login` and one protected-shell placeholder deep-link correctly after refresh.

**Verification:**
- [ ] Run `npm run check` and `npm run build`.
- [ ] Serve the build through the target Nginx topology and refresh both routes.

**Dependencies:** Tasks 2–4

**Files likely touched:** `src/app.html`, `src/routes/+layout.svelte`, `src/routes/+layout.ts`, `src/routes/+error.svelte`, `svelte.config.js`

**Estimated scope:** M — 5 files

## Task 6: Generate OpenAPI transport types

**Description:** Add reproducible generation from the approved OpenAPI commit and a drift check that prevents handwritten or stale DTOs.

**Acceptance criteria:**
- [ ] Generated schemas preserve decimal strings, integer Rial values, discriminated section states, Problem Details, and SSE payloads.
- [ ] Generated files carry provenance and are never manually edited.
- [ ] CI/local check fails when approved OpenAPI and generated output differ.

**Verification:**
- [ ] Run generation twice and confirm no diff.
- [ ] Run the contract-drift command against a deliberate schema change, then restore it.

**Dependencies:** Tasks 1, 3–4

**Files likely touched:** `package.json`, `scripts/generate-api.mjs`, `src/lib/api/generated/schema.ts`, `docs/API-CONTRACT.md`

**Estimated scope:** M — 4 files

### Checkpoint A2 — Executable contract foundation

- [ ] Tasks 4–6 pass all configured checks.
- [ ] Static deep links and generated contract drift are proven.
- [ ] Human review confirms no server authority moved into the browser.

## Phase B — Design, transport, and identity

## Task 7: Implement the typed HTTP client boundary

**Description:** Build one same-origin fetch boundary for generated JSON operations, RFC 9457 errors, request ids, CSRF mutations, `Retry-After`, and session termination.

**Acceptance criteria:**
- [ ] UI code can branch on stable status/code without parsing server prose.
- [ ] Cookies use browser credentials policy while auth tokens never enter storage or headers.
- [ ] `401`, safe `404`, `429`, retryable `503`, and validation field errors map to typed results.

**Verification:**
- [ ] Run focused unit tests for success/error/header mappings.
- [ ] Run `npm run check` and inspect logs/storage for sensitive values.

**Dependencies:** Task 6

**Files likely touched:** `src/lib/api/client.ts`, `src/lib/api/problem.ts`, `src/lib/api/client.test.ts`, `src/lib/api/problem.test.ts`

**Estimated scope:** M — 4 files

## Task 8: Implement tokens, font, and pre-paint theme

**Description:** Translate `DESIGN.md` `0.3.2` into global semantic CSS, load the tracked FaNum variable font, and apply system/explicit theme before paint.

**Acceptance criteria:**
- [ ] Components can consume semantic light/dark roles without raw palette values.
- [ ] `IRANYekanXVFaNumVF.woff2` loads from `static/fonts` with the approved fallback and weights.
- [ ] Theme choice persists as presentation-only state with no first-paint flash.

**Verification:**
- [ ] Run build plus focused theme bootstrap tests.
- [ ] Manually inspect first paint in light/dark/system modes and verify the license remains adjacent.

**Dependencies:** Tasks 3–5

**Files likely touched:** `src/app.css`, `src/app.html`, `src/routes/+layout.svelte`, `src/lib/components/ui/ThemeControl.svelte`, `src/lib/components/ui/ThemeControl.test.ts`

**Estimated scope:** M — 5 files

## Task 9: Create contract-safe fixture builders

**Description:** Create synthetic builders for sessions, periods, all run/section states, problems, detail pages, and SSE events without copying source data.

**Acceptance criteria:**
- [ ] Fixtures cover zero, null, empty, unavailable comparison, suppression, failure, rate limit, and replay reset.
- [ ] Builders typecheck against generated schemas and use distinct synthetic merchants.
- [ ] Forbidden payer/credential/peer-row fields are absent and scanned.

**Verification:**
- [ ] Run fixture type tests and forbidden-field scan.
- [ ] Regenerate API types and confirm fixture compilation detects drift.

**Dependencies:** Tasks 6–7

**Files likely touched:** `src/lib/testing/fixtures.ts`, `src/lib/testing/events.ts`, `src/lib/testing/problems.ts`, `src/lib/testing/fixtures.test.ts`

**Estimated scope:** M — 4 files

### Checkpoint B1 — Design and transport primitives

- [ ] Tasks 7–9 pass focused tests and production build.
- [ ] Theme/font work matches `DESIGN.md` without new system decisions.
- [ ] Fixtures contain no sensitive or peer-level source data.

## Task 10: Implement Persian financial formatters

**Description:** Centralize Persian digits, Rial-only money, exact decimal percentages, Jalali/Tehran dates, units, and LTR isolation metadata.

**Acceptance criteria:**
- [ ] Integer Rial/count values and decimal strings format without unintended floating-point changes.
- [ ] Dates use Jalali/`Asia/Tehran`; technical ids remain canonical and bidi-safe.
- [ ] Zero, null, undefined, and unavailable states have distinct typed output.

**Verification:**
- [ ] Run table-driven unit tests for boundary, long, mixed-direction, and negative comparison values.
- [ ] Manually review representative Persian output with the FaNum font.

**Dependencies:** Tasks 8–9

**Files likely touched:** `src/lib/format/number.ts`, `src/lib/format/date.ts`, `src/lib/format/bidi.ts`, `src/lib/format/format.test.ts`

**Estimated scope:** M — 4 files

## Task 11: Deliver the login vertical slice

**Description:** Build the accessible Persian login screen and connect it to `createAuthSession` with generic, throttled, pending, and service-error states.

**Acceptance criteria:**
- [ ] Visible labels, password-manager autocomplete, paste, and generic credential failure match the UX spec.
- [ ] Pending submission prevents duplicates; `429` honors `Retry-After` without a retry loop.
- [ ] Successful login stores only the session summary/CSRF value in memory and navigates to the dashboard.

**Verification:**
- [ ] Run component/integration tests for success, invalid credentials, throttle, and dependency failure.
- [ ] Run keyboard and accessible-name checks at 360 px and desktop.

**Dependencies:** Tasks 7–10

**Files likely touched:** `src/routes/(auth)/login/+page.svelte`, `src/lib/components/auth/LoginForm.svelte`, `src/lib/features/auth/session.svelte.ts`, `src/lib/components/auth/LoginForm.test.ts`, `tests/e2e/login.spec.ts`

**Estimated scope:** M — 5 files

## Task 12: Deliver session restoration and logout

**Description:** Restore authorized session context on refresh, revoke it on logout, and clear merchant/run state on expiry or revocation.

**Acceptance criteria:**
- [ ] Refresh calls `getAuthSession` and renders only the server-returned merchant scope.
- [ ] Logout sends CSRF/origin evidence, clears memory after server revocation, and returns to login.
- [ ] `401` from HTTP or later stream recovery produces the approved generic session-ended flow.

**Verification:**
- [ ] Run focused auth-state tests and Playwright refresh/logout/expiry flows.
- [ ] Inspect storage, URL, and logs for session/CSRF/auth-token leakage.

**Dependencies:** Task 11

**Files likely touched:** `src/lib/features/auth/session.svelte.ts`, `src/routes/(app)/+layout.svelte`, `src/lib/components/auth/LogoutButton.svelte`, `src/lib/features/auth/session.test.ts`, `tests/e2e/session.spec.ts`

**Estimated scope:** M — 5 files

### Checkpoint B2 — Identity slice

- [ ] Tasks 10–12 pass all checks and runtime verification.
- [ ] Two synthetic/demo users remain tenant-isolated.
- [ ] Human review approves Persian login copy and session transitions.

## Phase C — Shell, periods, and partial analytics

## Task 13: Deliver the authenticated app shell

**Description:** Implement the RTL desktop sidebar, tablet/mobile drawer, utility header, skip link, merchant display name, theme control, and active navigation.

**Acceptance criteria:**
- [ ] `merchant.displayName` is identity context, never a selector.
- [ ] Drawer traps/restores focus, closes with Escape/backdrop, and locks background scroll.
- [ ] Navigation order, landmarks, `aria-current`, touch targets, and safe areas match the UX spec.

**Verification:**
- [ ] Run component tests plus Playwright keyboard navigation at 360/768/1024/1440.
- [ ] Run axe-equivalent checks in both themes.

**Dependencies:** Tasks 8, 12

**Files likely touched:** `src/lib/components/layout/AppShell.svelte`, `src/lib/components/layout/Sidebar.svelte`, `src/lib/components/layout/Drawer.svelte`, `src/routes/(app)/+layout.svelte`, `src/lib/components/layout/AppShell.test.ts`

**Estimated scope:** M — 5 files

## Task 14: Deliver reporting-period URL state

**Description:** Render server-allowlisted periods, select the backend default, and synchronize applied period state with navigation/history without client-computed boundaries.

**Acceptance criteria:**
- [ ] Default uses `isDefault`; options show `jalaliLabelFa` and approved types only.
- [ ] Apply/reset and Back/Forward restore valid URL state without fetching on pending edits.
- [ ] Unknown/stale period ids fail safely and never broaden scope.

**Verification:**
- [ ] Run unit/component tests for default, apply, reset, invalid URL, and history restoration.
- [ ] Run Playwright period flow with Persian labels.

**Dependencies:** Tasks 7, 10, 13

**Files likely touched:** `src/lib/features/periods/periods.svelte.ts`, `src/lib/components/analytics/PeriodFilter.svelte`, `src/routes/(app)/dashboard/+page.svelte`, `src/lib/features/periods/periods.test.ts`, `tests/e2e/periods.spec.ts`

**Estimated scope:** M — 5 files

## Task 15: Resolve the SSE transport spike

**Description:** Test native `EventSource` against the approved contract and compare fetch streaming only where typed status/header behavior requires it.

**Acceptance criteria:**
- [ ] The chosen transport proves cookie auth, named heartbeats, replay/reset, cleanup, and one reconnect owner.
- [ ] Handling for connection limits, session end, liveness timeout, and duplicate event ids is documented.
- [ ] No third-party SSE dependency is added without measured need and approval.

**Verification:**
- [ ] Run a focused browser harness against scripted SSE fixtures for disconnect/replay/reset.
- [ ] Record the decision and rejected alternative in `docs/SSE-TRANSPORT.md`.

**Dependencies:** Tasks 1, 7, 9, 12

**Files likely touched:** `src/lib/api/analytics-stream.ts`, `src/lib/api/analytics-stream.test.ts`, `tests/e2e/fixtures/sse.ts`, `tests/e2e/sse-spike.spec.ts`, `docs/SSE-TRANSPORT.md`

**Estimated scope:** M — 5 files

### Checkpoint C1 — Shell, periods, and SSE decision

- [ ] Tasks 13–15 pass responsive, keyboard, and transport tests.
- [ ] Human review approves the SSE decision before run orchestration begins.
- [ ] No reconnect duplication or merchant-scope state survives logout.

## Task 16: Implement the analytics run reducer

**Description:** Create a pure, typed state reducer for run snapshots and all named SSE events, preserving independent ready sections and ignoring duplicates/regressions.

**Acceptance criteria:**
- [ ] All four sections support queued/calculating/ready/failed and peer suppression.
- [ ] Duplicate/replayed/out-of-order events cannot duplicate or erase valid ready results.
- [ ] Overall progress derives from section state without animation dependence.

**Verification:**
- [ ] Run exhaustive reducer tests for every state transition and duplicate event.
- [ ] Run generated-schema typecheck.

**Dependencies:** Tasks 9, 15

**Files likely touched:** `src/lib/features/analytics-run/model.ts`, `src/lib/features/analytics-run/reducer.ts`, `src/lib/features/analytics-run/reducer.test.ts`

**Estimated scope:** M — 3 files

## Task 17: Deliver run start, snapshot, and stream orchestration

**Description:** Connect applied period state to idempotent run creation, current snapshot recovery, the chosen stream, heartbeat watchdog, and authorized teardown.

**Acceptance criteria:**
- [ ] One applied period intent produces a stable idempotency key and no duplicate equivalent starts.
- [ ] Ready snapshot sections render immediately while unfinished siblings stream independently.
- [ ] Replay reset, stream close, period change, logout, and component teardown preserve correct ownership.

**Verification:**
- [ ] Run integration tests for `200`/`202`, replay, reset, period change, and teardown.
- [ ] Run Playwright with different section completion orders.

**Dependencies:** Tasks 14–16

**Files likely touched:** `src/lib/features/analytics-run/controller.svelte.ts`, `src/lib/components/analytics/RunStatus.svelte`, `src/routes/(app)/dashboard/+page.svelte`, `src/lib/features/analytics-run/controller.test.ts`, `tests/e2e/partial-run.spec.ts`

**Estimated scope:** M — 5 files

## Task 18: Deliver the overview vertical slice

**Description:** Render headline KPIs in approved order, exact comparisons, empty/undefined states, provenance, and stable loading/ready layout.

**Acceptance criteria:**
- [ ] Amount, count, success, and verification KPIs use correct semantics, Persian formatting, unit, period, and definitions.
- [ ] Unavailable baseline and undefined denominator never display as zero or trend.
- [ ] Overview becomes useful without waiting for other sections and does not steal focus.

**Verification:**
- [ ] Run component tests across queued/calculating/ready/empty/unavailable/failed fixtures.
- [ ] Run visual checks at four viewports in both themes.

**Dependencies:** Tasks 10, 17

**Files likely touched:** `src/lib/features/overview/OverviewSection.svelte`, `src/lib/components/analytics/MetricCard.svelte`, `src/lib/components/analytics/SectionFrame.svelte`, `src/lib/features/overview/OverviewSection.test.ts`, `src/routes/(app)/dashboard/+page.svelte`

**Estimated scope:** M — 5 files

### Checkpoint C2 — First complete analytics slice

- [ ] Tasks 16–18 pass focused tests, Playwright, check, and build.
- [ ] Idempotent start plus independently ready overview works end to end.
- [ ] Human review approves stable layout and restrained live announcements.

## Task 19: Deliver deterministic overview insights

**Description:** Render action cards only when the server comparison and approved evidence thresholds make the insight eligible.

**Acceptance criteria:**
- [ ] Insight copy includes observation, exact evidence, relevant sessions, possible action, and limitation.
- [ ] Below-threshold, zero-baseline, missing, or undefined comparisons never create action claims.
- [ ] Language remains observational and uses correct Persian percentage-point terminology.

**Verification:**
- [ ] Run table-driven component tests at 99/100 sessions and threshold boundaries.
- [ ] Manually review all Persian insight variants for causality and نیم‌فاصله.

**Dependencies:** Task 18

**Files likely touched:** `src/lib/features/overview/InsightCard.svelte`, `src/lib/features/overview/insights.ts`, `src/lib/features/overview/InsightCard.test.ts`

**Estimated scope:** M — 3 files

## Task 20: Deliver payment-performance outcomes and retry

**Description:** Render final outcomes, verification gap, observed stages, retry sessions, and recovery rate without misclassifying `Paid`, `NoAttempt`, or `InBank`.

**Acceptance criteria:**
- [ ] `Paid` and `Verified` are bank-paid while only `Verified` is finalized.
- [ ] Stage and retry values use session grain, exact denominators, and approved safe language.
- [ ] Chart/table alternatives expose the same labeled values without color-only meaning.

**Verification:**
- [ ] Run component tests for every status/stage and undefined retry rate.
- [ ] Run keyboard/table-equivalence and both-theme checks.

**Dependencies:** Tasks 17–18

**Files likely touched:** `src/lib/features/payment-performance/OutcomeSummary.svelte`, `src/lib/features/payment-performance/RetrySummary.svelte`, `src/lib/components/analytics/AccessibleChart.svelte`, `src/lib/features/payment-performance/payment-performance.test.ts`, `src/routes/(app)/payments/+page.svelte`

**Estimated scope:** M — 5 files

## Task 21: Deliver processing-time analysis

**Description:** Render init/verify p50 and p95 with sample and non-null coverage using an accessible paired visualization and table.

**Acceptance criteria:**
- [ ] Missing timing remains unavailable, never zero.
- [ ] Milliseconds are primary and readable seconds may only supplement them.
- [ ] Exact p50/p95/sample/coverage is available without hover or pointer precision.

**Verification:**
- [ ] Run component tests for null, zero, sparse, and full-coverage fixtures.
- [ ] Verify chart/table equivalence, Persian digits, and mobile height.

**Dependencies:** Tasks 10, 20

**Files likely touched:** `src/lib/features/payment-performance/TimingSummary.svelte`, `src/lib/features/payment-performance/TimingChart.svelte`, `src/lib/features/payment-performance/TimingSummary.test.ts`

**Estimated scope:** M — 3 files

### Checkpoint C3 — Payment performance

- [ ] Tasks 19–21 pass metric-semantic and accessibility checks.
- [ ] No actionable claim appears below approved thresholds.
- [ ] Human review confirms status/stage copy does not invent causes.

## Task 22: Deliver the fees vertical slice

**Description:** Render real session-grain paid fees, paid amount denominator, fee rate, comparison, and accessible trend/table in Rial only.

**Acceptance criteria:**
- [ ] Fee totals are labeled real merchant fees and never multiplied by attempts.
- [ ] Rial and percentage never share an ambiguous axis; undefined fee rate is explicit.
- [ ] Period, denominator, comparison, definition version, and calculation time are visible.

**Verification:**
- [ ] Run tests with duplicate attempts, zero denominator, unavailable baseline, and large Rial amounts.
- [ ] Run responsive/light/dark chart-table review.

**Dependencies:** Tasks 17–18

**Files likely touched:** `src/lib/features/fees/FeesSection.svelte`, `src/lib/features/fees/FeesChart.svelte`, `src/lib/features/fees/FeesSection.test.ts`, `src/routes/(app)/fees/+page.svelte`

**Estimated scope:** M — 4 files

## Task 23: Deliver the peer-comparison vertical slice

**Description:** Render approved merchant-weighted medians and direction-aware percentiles or the privacy-safe suppressed state.

**Acceptance criteria:**
- [ ] Higher displayed percentile always means better, with lower-is-better metrics explained.
- [ ] Suppression exposes no peer values/rows/identities and does not hide merchant analytics.
- [ ] Chart/table/labels cannot imply an individual peer distribution or rank.

**Verification:**
- [ ] Run ready/suppressed boundary fixtures and sensitive-field absence tests.
- [ ] Run accessible-name, keyboard, both-theme, and mobile checks.

**Dependencies:** Tasks 17–18

**Files likely touched:** `src/lib/features/peer-comparison/PeerSection.svelte`, `src/lib/features/peer-comparison/PeerMetric.svelte`, `src/lib/features/peer-comparison/PeerSection.test.ts`, `src/routes/(app)/peers/+page.svelte`

**Estimated scope:** M — 4 files

## Task 24: Deliver failure, retry, and recovery integration

**Description:** Integrate section-local failure/manual retry, rate limits, heartbeat loss, replay/reset, and overall status across all analytics pages.

**Acceptance criteria:**
- [ ] Manual retry targets one exhausted failed section and preserves ready siblings.
- [ ] `Retry-After` and connection recovery never create a tight loop or competing announcements.
- [ ] Heartbeats are silent while meaningful progress/recovery uses one restrained live region.

**Verification:**
- [ ] Run integration/Playwright tests for mixed terminal states, retry conflicts, `429`, disconnect, and reset.
- [ ] Screen-reader check confirms no heartbeat/countdown announcement spam.

**Dependencies:** Tasks 19–23

**Files likely touched:** `src/lib/features/analytics-run/controller.svelte.ts`, `src/lib/components/analytics/SectionError.svelte`, `src/lib/components/analytics/RunStatus.svelte`, `src/lib/features/analytics-run/recovery.test.ts`, `tests/e2e/recovery.spec.ts`

**Estimated scope:** M — 5 files

### Checkpoint C4 — Complete partial analytics

- [ ] Tasks 22–24 pass all section-state and recovery scenarios.
- [ ] All four sections are independently useful in any completion order.
- [ ] Human review approves charts/tables, suppression, rate-limit, and recovery UX.

## Phase D — Merchant-owned evidence and CSV

## Task 25: Implement the cursor-detail client and table foundation

**Description:** Build typed detail queries, opaque-cursor URL state, server pagination, semantic desktop table, and mobile priority-row disclosure.

**Acceptance criteria:**
- [ ] View/period/allowlisted filters come from URL while cursor changes cannot broaden scope.
- [ ] Page size follows the contract and no browser-side total/fake pagination is invented.
- [ ] Table captions, headers, row disclosures, sort/order statement, and LTR ids are accessible.

**Verification:**
- [ ] Run integration tests for next cursor, invalid cursor, filter change, empty, and `404`.
- [ ] Run 320/360 px reflow plus keyboard/screen-reader table checks.

**Dependencies:** Tasks 10, 13–14, 24

**Files likely touched:** `src/lib/features/session-details/client.ts`, `src/lib/features/session-details/state.svelte.ts`, `src/lib/components/details/DetailTable.svelte`, `src/lib/components/details/DetailRow.svelte`, `src/lib/features/session-details/details.test.ts`

**Estimated scope:** M — 5 files

## Task 26: Deliver the unverified-paid detail view

**Description:** Provide read-only merchant-owned `Paid` evidence with accurate bank-paid/unverified language and empty/error states.

**Acceptance criteria:**
- [ ] Only the approved `UNVERIFIED_PAID` view/fields are requested and rendered.
- [ ] `Paid` is never styled or announced as failure.
- [ ] Period, result context, amounts in Rial, ids, attempts, and export eligibility are explicit.

**Verification:**
- [ ] Run focused route/component tests for rows, empty, cursor, and session expiry.
- [ ] Reconcile fixture rows with the unverified aggregate.

**Dependencies:** Task 25

**Files likely touched:** `src/routes/(app)/payments/unverified/+page.svelte`, `src/lib/features/session-details/UnverifiedPaidView.svelte`, `src/lib/features/session-details/UnverifiedPaidView.test.ts`

**Estimated scope:** M — 3 files

## Task 27: Deliver the failed-session detail view

**Description:** Provide read-only failed-session evidence with allowlisted observed-stage filters and no invented bank/PSP causes.

**Acceptance criteria:**
- [ ] Only `NO_ATTEMPT`, `REACHED_BANK`, and `OTHER_OBSERVED` filters are available.
- [ ] `NoAttempt` and `InBank` copy preserves approved observed-stage meaning.
- [ ] Filter/cursor manipulation returns safe typed errors without cross-tenant hints.

**Verification:**
- [ ] Run focused tests for each stage, empty, invalid cursor/filter, and safe `404`.
- [ ] Manually review Persian stage copy against the metric catalogue.

**Dependencies:** Task 25

**Files likely touched:** `src/routes/(app)/payments/failed/+page.svelte`, `src/lib/features/session-details/FailedView.svelte`, `src/lib/components/details/FailureStageFilter.svelte`, `src/lib/features/session-details/FailedView.test.ts`

**Estimated scope:** M — 4 files

### Checkpoint D1 — First detail views

- [ ] Tasks 25–27 pass cursor, responsive-table, and privacy checks.
- [ ] Aggregates remain reconciliation source; no unbounded client count query exists.
- [ ] Human review confirms row priority and observed-stage language.

## Task 28: Deliver the retried-session detail view

**Description:** Provide read-only retried-session evidence with bounded ordered attempt summaries and eventual payment outcome.

**Acceptance criteria:**
- [ ] Attempt sequences are ordered, bounded, and never depend on source row order.
- [ ] Payer tokens, response codes, and undocumented causes remain absent.
- [ ] `Paid` or `Verified` eventual recovery is represented accurately.

**Verification:**
- [ ] Run tests for multiple attempts, long bounded history, null timing, and recovered/unrecovered outcomes.
- [ ] Reconcile fixture rows with retry aggregates.

**Dependencies:** Task 25

**Files likely touched:** `src/routes/(app)/payments/retried/+page.svelte`, `src/lib/features/session-details/RetriedView.svelte`, `src/lib/components/details/AttemptHistory.svelte`, `src/lib/features/session-details/RetriedView.test.ts`

**Estimated scope:** M — 4 files

## Task 29: Resolve synchronous CSV delivery behavior

**Description:** Measure and document direct navigation versus authenticated fetch/Blob at the approved cap, including typed errors and interrupted streams.

**Acceptance criteria:**
- [ ] Selected approach handles `413`, `429`, `504`, session expiry, and pre-byte failures truthfully.
- [ ] Memory/mobile behavior is measured at representative and maximum approved sizes.
- [ ] UX “requesting/downloading/failed” copy is amended if separate generating/ready states are not observable.

**Verification:**
- [ ] Run browser tests against success, Problem Details, and interrupted CSV fixtures.
- [ ] Record the decision and measurements in `docs/CSV-DELIVERY.md` before export UI work.

**Dependencies:** Tasks 1, 7, 25

**Files likely touched:** `src/lib/features/export/csv-spike.ts`, `src/lib/features/export/csv-spike.test.ts`, `tests/e2e/csv-spike.spec.ts`, `docs/CSV-DELIVERY.md`, `docs/DASHBOARD-UX-SPEC.md`

**Estimated scope:** M — 5 files

## Task 30: Deliver the authorized CSV export slice

**Description:** Add scope preflight and server-owned synchronous CSV download to the three eligible detail views using the Task 29 decision.

**Acceptance criteria:**
- [ ] Preflight states merchant display name, view, period, filters, Rial unit, and sensitive-field exclusion.
- [ ] Export always reauthorizes the server endpoint and never assembles hidden browser rows.
- [ ] Empty, requesting/downloading, rate-limited, too-large, timeout, interrupted, and session-ended states are distinct.

**Verification:**
- [ ] Run component/Playwright tests for all three views and every typed export outcome.
- [ ] Scan downloaded fixtures for BOM/header/timestamp/Rial policy and forbidden fields/formulas.

**Dependencies:** Tasks 26–29

**Files likely touched:** `src/lib/features/export/ExportDialog.svelte`, `src/lib/features/export/download.ts`, `src/lib/features/export/ExportDialog.test.ts`, `tests/e2e/export.spec.ts`, `src/lib/components/details/DetailTable.svelte`

**Estimated scope:** M — 5 files

### Checkpoint D2 — Evidence and export

- [ ] Tasks 28–30 pass reconciliation, cap/error, interruption, and privacy checks.
- [ ] Finance/legal handoff copy and synchronous behavior receive human approval.
- [ ] No payer token, peer row, credential, or other-merchant value reaches DOM/download/logs.

## Phase E — Completion and hardening

## Task 31: Deliver methodology and account screens

**Description:** Implement metric/period/lifecycle/coverage/peer/insight explanations plus account identity, theme, logout, and demo merchant-switch guidance.

**Acceptance criteria:**
- [ ] Definitions are linkable, versioned, keyboard reachable, and consistent with approved contracts.
- [ ] Account uses `merchant.displayName` and explains switching only by logout/new login.
- [ ] No profile editing, roles, registration, recovery, peer detail, or AI claims appear.

**Verification:**
- [ ] Run route/component tests and broken-anchor checks.
- [ ] Manually proofread Persian copy and mixed-direction identifiers.

**Dependencies:** Tasks 12–14, 19–24

**Files likely touched:** `src/routes/(app)/methodology/+page.svelte`, `src/lib/features/methodology/MetricDefinitions.svelte`, `src/routes/(app)/account/+page.svelte`, `src/lib/features/methodology/MetricDefinitions.test.ts`

**Estimated scope:** M — 4 files

## Task 32: Harden shell responsiveness and themes

**Description:** Complete shell/header/navigation/filter responsiveness, long Persian content handling, safe areas, focus visibility, and semantic dark-mode states.

**Acceptance criteria:**
- [ ] Shell/filter/navigation work at 360/768/1024/1440 and 320 CSS px reflow.
- [ ] Light/dark cover focus, hover, pressed, disabled, skeleton, scrim, status, and native controls.
- [ ] No sticky/fixed UI obscures focus or content.

**Verification:**
- [ ] Run responsive Playwright screenshots/interactions in both themes.
- [ ] Manually test 200% zoom, long merchant names, keyboard drawer, and reduced motion.

**Dependencies:** Tasks 13–14, 31

**Files likely touched:** `src/lib/components/layout/AppShell.svelte`, `src/lib/components/layout/Drawer.svelte`, `src/lib/components/analytics/PeriodFilter.svelte`, `src/app.css`, `tests/e2e/responsive-shell.spec.ts`

**Estimated scope:** M — 5 files

## Task 33: Harden analytics and detail responsiveness

**Description:** Complete KPI/chart/table/detail/export layout behavior, stable async footprints, content overflow, and mobile disclosure patterns.

**Acceptance criteria:**
- [ ] Section completion order causes no material layout shift or focus movement.
- [ ] Charts remain at least 240 px with exact value/table first-class alternatives.
- [ ] Detail/export tasks remain usable at 320 CSS px without hidden critical fields/actions.

**Verification:**
- [ ] Run visual regression and interaction checks across all routes/viewports/themes.
- [ ] Manually test long ids, maximum formatted values, empty/error/suppressed states.

**Dependencies:** Tasks 18–30

**Files likely touched:** `src/lib/components/analytics/SectionFrame.svelte`, `src/lib/components/analytics/AccessibleChart.svelte`, `src/lib/components/details/DetailTable.svelte`, `src/lib/features/export/ExportDialog.svelte`, `tests/e2e/responsive-data.spec.ts`

**Estimated scope:** M — 5 files

### Checkpoint E1 — Complete responsive product

- [ ] Tasks 31–33 pass all route, viewport, theme, and copy checks.
- [ ] No new design-system decision was introduced without `DESIGN.md` changelog.
- [ ] Human review approves the complete visual/interaction hierarchy.

## Task 34: Complete accessibility verification

**Description:** Close WCAG 2.2 AA gaps across authentication, shell, filters, async statuses, charts, tables, dialogs, and errors.

**Acceptance criteria:**
- [ ] Critical flows are keyboard complete with visible/restored/unobscured focus.
- [ ] Screen readers receive headings, labels, chart tables, associated errors, and restrained status messages.
- [ ] Automated checks have no serious/critical violations in both themes.

**Verification:**
- [ ] Run the full accessibility Playwright suite at acceptance viewports.
- [ ] Perform manual keyboard, screen-reader, 200% zoom/reflow, and reduced-motion checks.

**Dependencies:** Tasks 30–33

**Files likely touched:** `tests/e2e/accessibility.spec.ts`, `tests/e2e/keyboard.spec.ts`, `docs/ACCESSIBILITY-REPORT.md`, plus at most two focused defect files per implementation increment.

**Estimated scope:** M — split fixes into separate tasks if more than 5 files

## Task 35: Complete security and privacy negative tests

**Description:** Verify frontend behavior under manipulated ids/cursors/filters/events, session changes, hostile CSV/text content, and sensitive-field attempts.

**Acceptance criteria:**
- [ ] Cross-tenant/absent resources remain indistinguishable and clear no valid sibling data unexpectedly.
- [ ] Payer tokens, peer rows, cookies, CSRF/auth values, credentials, and internal keys never reach DOM/storage/URL/log/download.
- [ ] CSV formula prefixes and hostile bidi/long content remain safely presented.

**Verification:**
- [ ] Run security-focused unit/integration/Playwright tests and forbidden-field scans.
- [ ] Inspect browser storage/network/log artifacts for both demo merchants.

**Dependencies:** Tasks 24–34

**Files likely touched:** `tests/e2e/security.spec.ts`, `src/lib/testing/forbidden-fields.ts`, `src/lib/testing/forbidden-fields.test.ts`, `docs/SECURITY-VERIFICATION.md`

**Estimated scope:** M — 4 files

## Task 36: Verify the production static artifact

**Description:** Build the release candidate and exercise it behind the approved Nginx config with real proxy semantics for HTTP, SSE, CSV, fonts, and deep links.

**Acceptance criteria:**
- [ ] Lockfile install and all quality commands pass from a clean checkout.
- [ ] Deep-link refresh, immutable assets/font, `/api/v1`, SSE replay, and CSV download work through Nginx.
- [ ] No source map, env value, credential, generated secret, or unintended artifact is shipped.

**Verification:**
- [ ] Run the complete CI-equivalent command sequence and target-topology Playwright suite.
- [ ] Inspect build contents, response headers, caching, compression, and fallback routing.

**Dependencies:** Tasks 2, 34–35

**Files likely touched:** `tests/e2e/production.spec.ts`, `docs/PRODUCTION-VERIFICATION.md`, and up to three focused config/test files if defects are found.

**Estimated scope:** M — split defects if needed

### Checkpoint E2 — Release candidate

- [ ] Tasks 34–36 and the full Definition of Done pass.
- [ ] Product, accessibility, security, finance/legal export, and deployment evidence are reviewed.
- [ ] No deployment or release occurs without separate authorization.

## Task 37: Finalize implementation documentation

**Description:** Reconcile README, specs, plan, completed checklist, commands, source structure, transport decisions, and verification reports with the implemented state.

**Acceptance criteria:**
- [ ] Documentation describes current behavior and exact commands without stale draft assumptions.
- [ ] Durable SSE/CSV/chart/static decisions are linked and surprising decisions receive ADRs where required.
- [ ] Completed tasks and remaining limitations are accurate; no secret or private operational value is documented.

**Verification:**
- [ ] Run markdown/link/diff checks and compare every acceptance criterion with evidence.
- [ ] Obtain final human review before merge/release handoff.

**Dependencies:** Task 36

**Files likely touched:** `README.md`, `docs/DASHBOARD-SPEC.md`, `docs/DASHBOARD-UX-SPEC.md`, `tasks/plan.md`, `tasks/todo.md`

**Estimated scope:** M — 5 files

## Final implementation gate

- [ ] Human approves this Phase 3 task list.
- [ ] Tasks 1–2 are complete before Task 3 begins.
- [ ] Implementation proceeds one task at a time with tests first where behavior/logic changes.
- [ ] Every completed increment is verified and committed atomically without pushing unless separately requested.