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/tests/system/.pi-map.index.md

@@ -0,0 +1,20 @@
+# apps/api/tests/system (index)
+dir: apps/api/tests/system
+
+## role
+System-level integration test suite for the API application.
+## parent
+index: apps/api/tests/.pi-map.index.md
+map: apps/api/tests/.pi-map.md
+## children
+-
+## files
+- __init__.py
+## links
+index: apps/api/tests/system/.pi-map.index.md
+map: apps/api/tests/system/.pi-map.md
+## workflows
+- change system behavior
+  read: __init__.py
+## dirty
+-

apps/api/tests/system/.pi-map.md

@@ -0,0 +1,20 @@
+# apps/api/tests/system
+dir: apps/api/tests/system
+
+index: apps/api/tests/system/.pi-map.index.md
+
+## role
+System-level integration test suite for the API application.
+## files
+- __init__.py | Empty file with no functionality
+## arch
+Minimal test package structure with placeholder initialization, following Python package conventions for future test module organization.
+## tags
+init, empty, functionality
+## symbols
+-
+## workflows
+- change system behavior
+  read: __init__.py
+## dirty
+-