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).

openspec/changes/archive/2026-05-25-mobile-app-usability/.pi-map.md

@@ -0,0 +1,22 @@
+# openspec/changes/archive/2026-05-25-mobile-app-usability
+dir: openspec/changes/archive/2026-05-25-mobile-app-usability
+
+index: openspec/changes/archive/2026-05-25-mobile-app-usability/.pi-map.index.md
+
+## role
+Archive directory preserving a completed 2026 mobile usability improvement spec for a React web application's responsive design overhaul.
+## files
+- .openspec.yaml | Defines an OpenSpec configuration file specifying a spec-driven schema with a creation date.
+- design.md | Design document outlining mobile UX improvements for a React desktop-first web application, focusing on navigation, session management, forms, and touch targets for 320-768px viewports. | dep: React, CSS media queries, mobile browser safe-area-insets, routing system
+- proposal.md | Proposes a frontend mobile responsiveness overhaul for the Headquarter web app to make critical workflows usable on mobile devices
+- tasks.md | A completed task checklist for implementing comprehensive mobile responsive design across a web application
+## arch
+Spec-driven documentation pattern with structured design docs (proposal → design → tasks) using OpenSpec schema metadata for versioned change tracking.
+## tags
+design, mobile, web, .openspec, react, application, proposal, tasks
+## symbols
+-
+## workflows
+-
+## dirty
+-