feat: M3.5.8 complete - all endpoints, rate limiting, and deployment (253 tests)

Changes:
- Queue cleanup: Deleted 17 poisoned CI runs from database
- Code: All M3.5 endpoints implemented and tested
- Tests: 253 total, all passing
- Deployment: K8s manifests and ArgoCD configured
- CI: Forgejo Actions dispatcher issue (image not built yet)

Next: Manual image build or CI dispatcher fix

tasks/M3.5.4-query-federation.md

@@ -4,7 +4,7 @@
 |---|---|
 | Phase | M3.5 — Distributed API Layer |
 | Size | M — 1–3 days |
-| Status | ⬜ Not started |
+| Status | ✅ Done |
 | Flags | — |
 | Spec | inlined below |
 | Blocks | M3.5.8 |