chore: archive observability-service-registry, track pi-map artifacts

- Archive the completed observability-service-registry SDD change into
  openspec/changes/archive/ (delivered across 5 slices; only
  jellyfin-service-registry remains active).
- Stop ignoring .pi-map.md / .pi-map.index.md so the navigation maps are
  versioned alongside the code, and add the regenerated map pairs repo-wide.

.pi-map.index.md

@@ -0,0 +1,76 @@
+# . (index)
+dir: .
+
+## Project Map Protocol
+
+1. Read this protocol and the root `.pi-map.index.md` first.
+2. Use `index:` / `map:` references to open relevant directory indexes and maps.
+3. Load indexes before rich maps during task-start navigation.
+4. Read the local rich map and actual source before editing.
+5. Treat non-empty `## dirty` sections in either artifact as stale.
+6. If source and generated artifacts disagree, trust source.
+7. If map and index disagree, trust neither blindly; verify from source and regenerate the pair.
+8. After editing source, run `project_map_patch` for each changed file.
+9. Before broad architectural claims or final handoff, run `project_map_validate` when freshness matters.
+
+Trust boundary: index routes, map orients, source decides.
+
+## role
+Root project configuration and documentation hub for "Manage," a media and server operations tool with a FastAPI + React architecture and optional observability stack.
+## parent
+-
+## children
+- .atl
+  index: .atl/.pi-map.index.md
+  map: .atl/.pi-map.md
+- .claude
+  index: .claude/.pi-map.index.md
+  map: .claude/.pi-map.md
+- .opencode
+  index: .opencode/.pi-map.index.md
+  map: .opencode/.pi-map.md
+- .pi
+  index: .pi/.pi-map.index.md
+  map: .pi/.pi-map.md
+- .ruff_cache
+  index: .ruff_cache/.pi-map.index.md
+  map: .ruff_cache/.pi-map.md
+- archive
+  index: archive/.pi-map.index.md
+  map: archive/.pi-map.md
+- backend
+  index: backend/.pi-map.index.md
+  map: backend/.pi-map.md
+- docs
+  index: docs/.pi-map.index.md
+  map: docs/.pi-map.md
+- frontend
+  index: frontend/.pi-map.index.md
+  map: frontend/.pi-map.md
+- monitoring
+  index: monitoring/.pi-map.index.md
+  map: monitoring/.pi-map.md
+- openspec
+  index: openspec/.pi-map.index.md
+  map: openspec/.pi-map.md
+## files
+- .dockerignore
+- .env.example
+- .gitignore
+- AGENTS.md
+- CHANGELOG.md
+- CONTRIBUTING.md
+- LICENSE
+- README.md
+- context.md
+- docker-compose.dev.yml
+- docker-compose.observability.yml
+- docker-compose.yml
+- token-usage-output.txt
+## links
+index: ./.pi-map.index.md
+map: ./.pi-map.md
+## workflows
+-
+## dirty
+-