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/features/.pi-map.index.md

@@ -0,0 +1,28 @@
+# docs/features (index)
+dir: docs/features
+
+## role
+User-facing documentation for features of the "Headquarter" developer platform application, covering authentication, project/repository management, git tools, web-based terminals, and workspace editing.
+## parent
+index: docs/.pi-map.index.md
+map: docs/.pi-map.md
+## children
+-
+## files
+- auth.md
+- git-history.md
+- projects.md
+- repositories.md
+- settings.md
+- ssh-keys.md
+- terminal-troubleshooting.md
+- terminal.md
+- tool-types.md
+- workspace.md
+## links
+index: docs/features/.pi-map.index.md
+map: docs/features/.pi-map.md
+## workflows
+-
+## dirty
+-