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).

.stoneforge/sync/.pi-map.md

@@ -0,0 +1,20 @@
+# .stoneforge/sync
+dir: .stoneforge/sync
+
+index: .stoneforge/sync/.pi-map.index.md
+
+## role
+Distributed task coordination and ephemeral worker agent management for a multi-agent execution system.
+## files
+- dependencies.jsonl | Stores a sequence of dependency relationships between entities in JSON Lines format, tracking parent-child, blocking, and reply relationships with timestamps and creators.
+- elements.jsonl | Stores JSONL records of ephemeral worker agents with their session history, worktree assignments, and lifecycle metadata for a distributed task execution system.
+## arch
+Event-sourced JSONL append-only logs with entity-relationship graph tracking, session-based worker lifecycle management, and decentralized worktree assignment.
+## tags
+stores, relationships, dependencies, elements, sequence, dependency, entities, json
+## symbols
+-
+## workflows
+-
+## dirty
+-