Pi skill integration, CLI polish, --fix flag, config file support

- SKILL.md: Proper Agent Skills frontmatter with name/description
- pi-extension.ts: Pi extension registering 4 custom tools
  (project_map_init/patch/validate/reinit) with prompt snippets/guidelines
- pi-extension.ts: Auto-detects .pi-map.md files on session start, warns
  about dirty markers, injects maintenance hints before agent start
- package.json: Added pi.extensions and pi.skills entries
- CLI: Added picocolors, clean help screen, progress indicators,
  summary output with timing, colored check/warning icons
- validate.ts: Added --fix flag that regenerates directories with
  discrepancies
- config.ts: Reads .pi-project-map.json from project root with merge
  over defaults
- init.ts: Added optional verbose parameter for programmatic use

All 16 tests pass. TypeScript compiles clean. Build succeeds.

package.json

@@ -23,6 +23,14 @@
   ],
   "author": "",
   "license": "MIT",
+  "pi": {
+    "extensions": [
+      "./pi-extension.ts"
+    ],
+    "skills": [
+      "./SKILL.md"
+    ]
+  },
   "devDependencies": {
     "@types/node": "^20.0.0",
     "@typescript-eslint/eslint-plugin": "^6.0.0",
@@ -34,6 +42,7 @@
   },
   "dependencies": {
     "ignore": "^5.3.0",
+    "picocolors": "^1.1.1",
     "tree-sitter": "^0.21.0",
     "tree-sitter-go": "^0.25.0",
     "tree-sitter-python": "^0.25.0",