chore: track all project map and index files

Add generated .pi-map.md and .pi-map.index.md files across the repository
so the project navigation maps are shared and versioned. These artifacts
are maintained by project_map_init/patch/validate and must be kept in
sync with source edits.

Note: .cache/ remains ignored (added in previous commit).

apps/api/.pi-map.index.md

@@ -0,0 +1,39 @@
+# apps/api (index)
+dir: apps/api
+
+## role
+Backend API server providing project management, git repository operations, and development tool orchestration via Docker containers.
+## parent
+index: apps/.pi-map.index.md
+map: apps/.pi-map.md
+## children
+- apps/api/.pi-lens
+  index: apps/api/.pi-lens/.pi-map.index.md
+  map: apps/api/.pi-lens/.pi-map.md
+- apps/api/alembic
+  index: apps/api/alembic/.pi-map.index.md
+  map: apps/api/alembic/.pi-map.md
+- apps/api/src
+  index: apps/api/src/.pi-map.index.md
+  map: apps/api/src/.pi-map.md
+- apps/api/tests
+  index: apps/api/tests/.pi-map.index.md
+  map: apps/api/tests/.pi-map.md
+- apps/api/uploads
+  index: apps/api/uploads/.pi-map.index.md
+  map: apps/api/uploads/.pi-map.md
+## files
+- .dockerignore
+- Dockerfile
+- README.md
+- alembic.ini
+- pyproject.toml
+- uv.lock
+- wait-for-db.sh
+## links
+index: apps/api/.pi-map.index.md
+map: apps/api/.pi-map.md
+## workflows
+-
+## dirty
+-