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/uploads/avatars/.pi-map.index.md

@@ -0,0 +1,22 @@
+# apps/api/uploads/avatars (index)
+dir: apps/api/uploads/avatars
+
+## role
+Storage directory for user avatar image files uploaded through the API.
+## parent
+index: apps/api/uploads/.pi-map.index.md
+map: apps/api/uploads/.pi-map.md
+## children
+-
+## files
+- 30d2810a-cb00-4065-8e5d-c7d32a0b55c9.png
+- b342b640-d3c1-488d-bdba-0e2890d6c363.png
+- da1c3121-20d7-400c-8c94-507a9d890810.png
+- ee9fdd89-0dcc-4f46-9ad8-01f4ff93720d.png
+## links
+index: apps/api/uploads/avatars/.pi-map.index.md
+map: apps/api/uploads/avatars/.pi-map.md
+## workflows
+-
+## dirty
+-