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/system/.pi-map.md

@@ -0,0 +1,25 @@
+# apps/api/src/schemas/system
+dir: apps/api/src/schemas/system
+
+index: apps/api/src/schemas/system/.pi-map.index.md
+
+## role
+Provides Pydantic schemas for system health monitoring endpoints in the API.
+## files
+- __init__.py | Re-exports health check schema classes from a submodule to provide a unified interface for the system schemas module. | dep: src.schemas.system.health
+- health.py | Defines Pydantic data models for health check API responses including database, disk, and overall system health status. | exp: class:DatabaseHealth, class:DiskHealth, class:HealthChecks, class:HealthResponse, class:DatabaseHealthResponse | dep: pydantic
+## arch
+Simple submodule pattern with explicit re-exports in __init__.py, using Pydantic models for structured API response validation.
+## tags
+health, database, response, system, disk, check, schemas, init
+## symbols
+- DatabaseHealth
+- DiskHealth
+- HealthChecks
+- HealthResponse
+- DatabaseHealthResponse
+## workflows
+- change system behavior
+  read: __init__.py, health.py
+## dirty
+-