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).

.claude/.pi-map.md

@@ -0,0 +1,18 @@
+# .claude
+dir: .claude
+
+index: .claude/.pi-map.index.md
+
+## role
+Configuration and instruction files for the Claude AI assistant integration.
+## files
+## arch
+Simple flat-file configuration storage with no complex architecture; contains prompt templates, system instructions, or context files used to guide Claude's behavior in this project.
+## tags
+-
+## symbols
+-
+## workflows
+-
+## dirty
+-