feat(#462): add federation scope enforcement service (#672)

docs/scratchpads/462-fed-m3-04-scope-service.md

@@ -0,0 +1,60 @@
+# Scratchpad — FED-M3-04 Scope Service
+
+## Objective
+
+Implement `apps/gateway/src/federation/server/scope.service.ts` for the M3 inbound federation scope-enforcement pipeline.
+
+## Scope / Constraints
+
+- Task: FED-M3-04, issue #462.
+- Branch: `feat/federation-m3-scope-service` from `origin/main` @ 0.0.48.
+- Pure service: no direct DB access; native RBAC/data access is injected per evaluation call.
+- Reuse `parseFederationScope` from M2-03.
+- Workers do not edit `docs/federation/TASKS.md` per repo AGENTS.md.
+
+## Acceptance Criteria
+
+1. Resource allowlist and `excluded_resources` enforced.
+2. Native RBAC evaluated as `subjectUserId` through an injected evaluator.
+3. Scope filter intersection supports `include_teams` and `include_personal` without widening native RBAC.
+4. `max_rows_per_query` caps requested limits.
+5. Service returns `{ allowed: true, filter }` or a structured deny reason usable by M4 audit.
+6. Unit tests cover every deny path.
+
+## Plan
+
+1. Inspect existing federation scope/schema/auth guard contracts.
+2. Add pure `FederationScopeService` plus typed result/filter/deny interfaces.
+3. Add focused unit tests for happy paths, filter intersection, row cap, and deny paths.
+4. Export/register service for future verb controllers.
+5. Run situational tests, baseline gates, code review, then PR.
+
+## Budget
+
+- Provided model tier: sonnet.
+- Estimate from task row: 10K tokens.
+- Working cap assumption: keep implementation focused to FED-M3-04 surfaces only.
+
+## Progress
+
+- Intake complete; dirty base worktree avoided by creating isolated worktree at `/home/jarvis/src/mosaic-mono-v1-fed-m3-04`.
+- Project PRD and federation task spec reviewed.
+- Added `FederationScopeService` with structured allow/deny result types and injected native RBAC evaluator contract.
+- Added unit coverage for happy path, row cap, filter intersection, and every deny path.
+- Exported/registered the service for upcoming M3 verb controllers.
+
+## Verification Evidence
+
+- `pnpm --filter @mosaicstack/gateway test -- src/federation/server/__tests__/scope.service.spec.ts` — pass (10 tests before review update; 11 tests after adding include_personal no-leak coverage).
+- `pnpm build` — pass (23 successful tasks).
+- `pnpm typecheck` — pass (41 successful tasks; re-run after review update).
+- `pnpm lint` — pass (23 successful tasks; re-run after review update).
+- `pnpm format:check` — pass (re-run after review update).
+- `pnpm test` — pass after starting local `postgres`/`valkey` and running `pnpm --filter @mosaicstack/db db:push` for the DB-backed cross-user isolation suite (41 successful tasks; gateway 477 passed / 11 skipped).
+- Code review: `~/.config/mosaic/tools/codex/codex-code-review.sh --uncommitted` — approve, 0 findings.
+- Security review: `~/.config/mosaic/tools/codex/codex-security-review.sh --uncommitted` — risk none, 0 findings.
+
+## Risks / Blockers
+
+- Issue #462 is already closed in provider output; likely milestone tracking mismatch. Will still reference #462 in PR body unless orchestrator redirects.
+- Local full-test setup required `docker compose up -d postgres valkey` + `db:push`; containers were stopped with `docker compose down` after verification.