Implement all stubs: parsePackageMap, LLM heuristics, tree-sitter AST, patch rewrite, reinit

- format.ts: Full parsePackageMap implementation with round-trip support
- llm-extract.ts: Heuristic-based extraction without LLM API (regex exports,
  imports, purpose inference from filename patterns)
- ast-extract.ts: Tree-sitter integration for TypeScript/TSX with fallback
  for other languages
- init.ts: Refactored to expose generateDirectoryMap helper, reinitPath
  delegates to initProject
- patch.ts: Small packages now use generateDirectoryMap for full rewrite
- discover.ts: Cleaned up require('fs') to use proper ES import
- Tests: 8 tests covering format round-trip and LLM heuristics
- All TypeScript compiles clean, all tests pass

src/cli.ts

@@ -1,32 +1,32 @@
 #!/usr/bin/env node
-import { initProject } from './init.js';
-import { patchFile } from './patch.js';
-import { validateMaps } from './validate.js';
-import { reinitPath } from './init.js';
+import { initProject } from "./init.js";
+import { patchFile } from "./patch.js";
+import { validateMaps } from "./validate.js";
+import { reinitPath } from "./init.js";
 
 const args = process.argv.slice(2);
 const command = args[0];
 
 async function main() {
-  switch (command) {
-    case 'init':
-      await initProject(args[1] || '.');
-      break;
-    case 'patch':
-      await patchFile(args[1]);
-      break;
-    case 'validate': {
-      const result = await validateMaps(args[1] || '.');
-      process.exit(result.clean ? 0 : 1);
-      break;
-    }
-    case 'reinit':
-      await reinitPath(args[1] || '.');
-      break;
-    default:
-      console.log(`Usage: project-map <init|patch|validate|reinit> [path]`);
-      process.exit(1);
-  }
+	switch (command) {
+		case "init":
+			await initProject(args[1] || ".");
+			break;
+		case "patch":
+			await patchFile(args[1]);
+			break;
+		case "validate": {
+			const result = await validateMaps(args[1] || ".");
+			process.exit(result.clean ? 0 : 1);
+			break;
+		}
+		case "reinit":
+			await reinitPath(args[1] || ".");
+			break;
+		default:
+			console.log(`Usage: project-map <init|patch|validate|reinit> [path]`);
+			process.exit(1);
+	}
 }
 
 main();