docs(spec): align dashboard implementation contracts

docs/DASHBOARD-UX-SPEC.md

@@ -401,7 +401,7 @@ Do not reveal which threshold failed, a near-threshold count that could aid diff
 - Payment lifecycle: why `Paid` and `Verified` are bank successes and only `Verified` is finalized.
 - Coverage: unknown statuses, timing non-null coverage, sample counts, and missing baseline behavior.
 - Peer privacy: equal-per-merchant median, direction-aware percentile, suppression, and prohibited peer detail.
-- Calculation lifecycle: lazy first access, independent four-section delivery, revision/version trace, and 30-day disposable cache without implying TTL-based staleness.
+- Calculation lifecycle: lazy first access, independent four-section delivery, immutable dataset-snapshot/metric-version trace, and 30-day disposable cache without implying TTL-based staleness.
 - Insight policy: 100-session evidence floor and approved change thresholds; observational, not causal language.
 
 Definitions open as a page or anchored side panel. They are linkable, keyboard reachable, and do not trap important content inside hover-only tooltips.
@@ -451,7 +451,7 @@ Overall progress is written as a contextual message such as «۲ از ۴ بخش
 
 ### 10.3 Stale/freshness language
 
-The frontend does not label data stale merely because a Redis entry is old or its 30-day TTL is approaching. Revisioned source/cohort keys and metric-definition version determine reuse. “Stale” appears only if a future approved interface returns an explicit stale/quality state. During SSE interruption, ready data is labeled with its calculation timestamp and connection recovery state, not silently called current or stale.
+The frontend does not label data stale merely because a Redis entry is old or its 30-day TTL is approaching. The immutable completed-import dataset snapshot and metric-definition version determine reuse. “Stale” appears only if a future approved interface returns an explicit stale/quality state. During SSE interruption, ready data is labeled with its calculation timestamp and connection recovery state, not silently called current or stale.
 
 ### 10.4 Event ordering and duplication
 
@@ -771,7 +771,7 @@ Persian digits are applied to rendered variable values. Technical identifiers in
 
 ## 20. Implementation handoff checklist (after approval only)
 
-- Obtain approved machine-readable analytics, identity, detail, SSE, error, and export contracts.
+- Generate transport types only from approved backend `docs/openapi.yaml` version `1.0.0` and fail checks on drift.
 - Resolve static adapter/Nginx fallback behavior.
 - Verify that local, CI, and Docker builds consume the tracked FaNum variable font and retain its adjacent license file without external downloads.
 - Create implementation tasks for shell, formatting, authentication, filters, run/SSE state model, each canonical section, detail tables, export, themes, and tests.
@@ -780,9 +780,9 @@ Persian digits are applied to rendered variable values. Technical identifiers in
 
 No implementation work begins until the dashboard capability and this UX specification are explicitly approved.
 
-## 21. Remaining approval questions
+## 21. Resolved implementation handoff
 
-1. Approve or revise the backend draft CSV contract: synchronous delivery, eligible detail types/columns, UTF-8 BOM, ASCII `snake_case` headers, UTC timestamps, filename policy, 100,000-row/50-MiB caps, 60-second deadline, throttling, retention, and audit event.
-2. Should CSV preflight be a modal dialog on desktop or an inline disclosure, provided the mobile experience remains a focus-managed full-screen dialog/sheet?
-3. Approve the draft `AuthSession.merchant.displayName` field as authoritative for the shell and export preflight when the demo username differs.
-4. Is a downloadable chart-data table required in MVP, or is a visible semantic table alternative sufficient while CSV remains limited to authorized detail views?
+- CSV follows the approved backend contract: synchronous merchant-detail export, Persian headers, UTF-8 BOM, UTC timestamps, safe filename, 100,000-row/50-MiB/60-second caps, throttling, and 90-day analytics/export audit retention.
+- Export confirmation may use a compact inline disclosure on desktop and a focus-managed full-screen dialog/sheet on narrow screens.
+- `AuthSession.merchant.displayName` is authoritative for the shell and export confirmation when it differs from the demo username.
+- Every chart has a visible semantic table alternative. CSV remains limited to approved merchant-owned detail views; chart-data download is not a separate MVP export.