Initial commit: pi-project-map skill scaffolding

- Design doc with full spec (dense markdown format, hybrid AST+LLM pipeline,
  consumption model, stale data mitigation)
- Implementation plan with 6 milestones and rollout strategy
- TypeScript package structure with all source stubs
- CLI entry point, formatter, discover, init, patch, validate, extract, merge
- Pi SKILL.md with tool definitions and format documentation

README.md

@@ -0,0 +1,22 @@
+# pi-project-map
+
+Pi skill for hierarchical project analysis.
+
+## What it does
+
+Generates `.pi-map.md` files throughout your project — one per directory — containing a dense, machine-readable summary of that directory's files, exports, dependencies, and architecture. This gives Pi agents instant project comprehension without reading every source file.
+
+## Quick Start
+
+```bash
+npm install -g pi-project-map
+project-map init
+```
+
+## Design
+
+See [design-doc.md](design-doc.md) for the full specification.
+
+## Implementation Plan
+
+See [implementation-plan.md](implementation-plan.md) for the engineering roadmap.