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).

e2e/.pi-map.index.md

@@ -0,0 +1,27 @@
+# e2e (index)
+dir: e2e
+
+## role
+Provides automated end-to-end browser testing for the headquarter application using Playwright.
+## parent
+index: ./.pi-map.index.md
+map: ./.pi-map.md
+## children
+- e2e/tests
+  index: e2e/tests/.pi-map.index.md
+  map: e2e/tests/.pi-map.md
+## files
+- package.json
+- playwright.config.ts
+## links
+index: e2e/.pi-map.index.md
+map: e2e/.pi-map.md
+## workflows
+- change e2e behavior
+  read: playwright.config.ts
+- change e2e config
+  read: package.json, playwright.config.ts
+- explore e2e subdirectories
+  index: e2e/tests/.pi-map.index.md
+## dirty
+-