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).

docs/.pi-map.md

@@ -0,0 +1,19 @@
+# docs
+dir: docs
+
+index: docs/.pi-map.index.md
+
+## role
+Central documentation hub and knowledge base for the Headquarter platform, providing navigation and access to all project guides, API references, and technical resources.
+## files
+- README.md | Serves as the main index and navigation hub for the Headquarter platform documentation, organizing links to feature guides, API docs, architecture, deployment, and development resources.
+## arch
+Static documentation structure using markdown-based content organization with hierarchical topic grouping (features, API, architecture, deployment, development) and a single-entry-point index pattern.
+## tags
+readme, serves, main, index, navigation, hub, headquarter, platform
+## symbols
+-
+## workflows
+-
+## dirty
+-