fix(terminal): avoid lazy-loading tool manifest in async websocket handler

The container-user resolver introduced in 9f72093 accessed
'tool_type.manifest', which triggers a SQLAlchemy lazy load inside the
async WebSocket coroutine and raises MissingGreenlet. Fetch the manifest
explicitly with db_session.get() instead, matching the pattern used in
instance_service.py.

- Replace relationship access with explicit async loads in
  _resolve_container_user().
- Add unit tests covering manifest, base-definition, legacy, and missing
  manifest cases.
- Update project map artifacts.

Quality gates: pytest tests/api tests/services/test_terminal_manager_multi.py tests/unit (247 passed), ruff check (clean).

.pi-map.index.md

@@ -16,7 +16,7 @@ dir: .
 Trust boundary: index routes, map orients, source decides.
 
 ## role
-A self-hosted development platform that manages projects, git repositories, and development tools with OAuth2 authentication, containerized via Docker Compose.
+Root configuration and documentation package for "Headquarter," a self-hosted project management platform with Git repository features, containing deployment configs, development tooling, and UI rework tracking documents.
 ## parent
 -
 ## children
@@ -32,6 +32,15 @@ A self-hosted development platform that manages projects, git repositories, and
 - .pi
   index: .pi/.pi-map.index.md
   map: .pi/.pi-map.md
+- .pi-lens
+  index: .pi-lens/.pi-map.index.md
+  map: .pi-lens/.pi-map.md
+- .pytest_cache
+  index: .pytest_cache/.pi-map.index.md
+  map: .pytest_cache/.pi-map.md
+- .ruff_cache
+  index: .ruff_cache/.pi-map.index.md
+  map: .ruff_cache/.pi-map.md
 - .sisyphus
   index: .sisyphus/.pi-map.index.md
   map: .sisyphus/.pi-map.md
@@ -53,12 +62,12 @@ A self-hosted development platform that manages projects, git repositories, and
 - scripts
   index: scripts/.pi-map.index.md
   map: scripts/.pi-map.md
+- tests
+  index: tests/.pi-map.index.md
+  map: tests/.pi-map.md
 - tool-images
   index: tool-images/.pi-map.index.md
   map: tool-images/.pi-map.md
-- uploads
-  index: uploads/.pi-map.index.md
-  map: uploads/.pi-map.md
 ## files
 - .env.example
 - .gitignore
@@ -68,6 +77,7 @@ A self-hosted development platform that manages projects, git repositories, and
 - README.md
 - docker-compose.traefik.yml
 - docker-compose.yml
+- package-lock.json
 - progress.md
 - swap-pane
 - ui-audit-spacing-typography.md