docs: record approved capability map

docs/decisions/0001-repository-topology.md

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+# ADR 0001: Three-repository topology
+
+- Status: Accepted
+- Date: 2026-08-20
+
+## Context
+
+The service needs independently testable/deployable frontend and backend code while retaining a single operational entry point patterned after Qlockify. Deployment-specific files must not pollute service repositories.
+
+## Decision
+
+Use three Git repositories: deployment, Go backend, and SvelteKit frontend. The deployment workspace clones the two service repositories into ignored `backend/` and `frontend/` directories and builds pinned revisions through the release workflow.
+
+## Consequences
+
+- Service changes can run focused CI and then trigger the deployment workflow.
+- Deployment remains the authoritative location for Compose, Nginx, backup/restore, and server automation.
+- A release manifest must record the exact commit SHA of each service; local nested checkouts alone are not sufficient provenance.
+- Cross-repository contract changes require coordinated, backward-compatible rollout or an explicit release plan.
+