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/src/schemas/.pi-map.md

@@ -0,0 +1,22 @@
+# apps/api/src/schemas
+dir: apps/api/src/schemas
+
+index: apps/api/src/schemas/.pi-map.index.md
+
+## role
+Defines Pydantic schemas for data validation, serialization, and API request/response models in the FastAPI application.
+## files
+- __init__.py | Empty file with no functionality
+## arch
+Modular schema organization following FastAPI/Pydantic patterns, with empty __init__.py indicating package initialization for future schema modules.
+## tags
+init, empty, functionality
+## symbols
+-
+## workflows
+- change schemas behavior
+  read: __init__.py
+- explore schemas subdirectories
+  index: apps/api/src/schemas/config/.pi-map.index.md, apps/api/src/schemas/project/.pi-map.index.md, apps/api/src/schemas/system/.pi-map.index.md
+## dirty
+-