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/models/user/.pi-map.index.md

@@ -0,0 +1,25 @@
+# apps/api/src/models/user (index)
+dir: apps/api/src/models/user
+
+## role
+Provides the core data models for user identity, authentication credentials, and personal configuration in the API's database layer.
+## parent
+index: apps/api/src/models/.pi-map.index.md
+map: apps/api/src/models/.pi-map.md
+## children
+-
+## files
+- __init__.py
+- ssh_key.py
+- user.py
+- user_config.py
+## links
+index: apps/api/src/models/user/.pi-map.index.md
+map: apps/api/src/models/user/.pi-map.md
+## workflows
+- change user behavior
+  read: __init__.py, ssh_key.py, user.py
+- change user config
+  read: user_config.py
+## dirty
+-