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/format.ts

@@ -1,40 +1,129 @@
 export interface PackageMapData {
-  path: string;
-  role: string;
-  files: FileEntry[];
-  arch: string;
-  dirty?: string;
+	path: string;
+	role: string;
+	files: FileEntry[];
+	arch: string;
+	dirty?: string;
 }
 
 export interface FileEntry {
-  name: string;
-  purpose: string;
-  exports: string[];
-  deps: string[];
+	name: string;
+	purpose: string;
+	exports: string[];
+	deps: string[];
 }
 
 export function renderPackageMap(data: PackageMapData): string {
-  const lines: string[] = [];
-  lines.push(`# ${data.path}`);
-  lines.push(`## role`);
-  lines.push(data.role);
-  lines.push(`## files`);
-  for (const file of data.files) {
-    const exp = file.exports.length > 0 ? `exp: ${file.exports.join(', ')}` : '';
-    const dep = file.deps.length > 0 ? `dep: ${file.deps.join(', ')}` : '';
-    const parts = [`- ${file.name} | ${file.purpose}`];
-    if (exp) parts.push(exp);
-    if (dep) parts.push(dep);
-    lines.push(parts.join(' | '));
-  }
-  lines.push(`## arch`);
-  lines.push(data.arch);
-  lines.push(`## dirty`);
-  lines.push(data.dirty || '-');
-  return `${lines.join('\n')}\n`;
+	const lines: string[] = [];
+	lines.push(`# ${data.path}`);
+	lines.push(`## role`);
+	lines.push(data.role);
+	lines.push(`## files`);
+	for (const file of data.files) {
+		const exp =
+			file.exports.length > 0 ? `exp: ${file.exports.join(", ")}` : "";
+		const dep = file.deps.length > 0 ? `dep: ${file.deps.join(", ")}` : "";
+		const parts = [`- ${file.name} | ${file.purpose}`];
+		if (exp) parts.push(exp);
+		if (dep) parts.push(dep);
+		lines.push(parts.join(" | "));
+	}
+	lines.push(`## arch`);
+	lines.push(data.arch);
+	lines.push(`## dirty`);
+	lines.push(data.dirty || "-");
+	return `${lines.join("\n")}\n`;
 }
 
-export function parsePackageMap(_markdown: string): PackageMapData {
-  // TODO: implement robust parser
-  throw new Error('parsePackageMap not yet implemented');
+export function parsePackageMap(markdown: string): PackageMapData {
+	const lines = markdown.split("\n").map((l) => l.trimEnd());
+	const result: PackageMapData = {
+		path: "",
+		role: "",
+		files: [],
+		arch: "",
+		dirty: "-",
+	};
+
+	let section: "none" | "role" | "files" | "arch" | "dirty" = "none";
+
+	for (const line of lines) {
+		if (line.startsWith("# ")) {
+			result.path = line.slice(2).trim();
+			continue;
+		}
+		if (line === "## role") {
+			section = "role";
+			continue;
+		}
+		if (line === "## files") {
+			section = "files";
+			continue;
+		}
+		if (line === "## arch") {
+			section = "arch";
+			continue;
+		}
+		if (line === "## dirty") {
+			section = "dirty";
+			continue;
+		}
+		if (line === "") continue;
+
+		switch (section) {
+			case "role":
+				result.role = line;
+				break;
+			case "files": {
+				if (!line.startsWith("- ")) continue;
+				const entry = parseFileLine(line);
+				if (entry) result.files.push(entry);
+				break;
+			}
+			case "arch":
+				result.arch = result.arch ? `${result.arch}\n${line}` : line;
+				break;
+			case "dirty":
+				result.dirty = line === "-" ? undefined : line;
+				break;
+		}
+	}
+
+	return result;
+}
+
+function parseFileLine(line: string): FileEntry | null {
+	// Format: - filename | purpose | exp: ... | dep: ...
+	const withoutPrefix = line.slice(2).trim();
+	const parts = withoutPrefix.split(" | ").map((p) => p.trim());
+
+	if (parts.length < 2) return null;
+
+	const name = parts[0];
+	const purpose = parts[1];
+	const exports: string[] = [];
+	const deps: string[] = [];
+
+	for (let i = 2; i < parts.length; i++) {
+		const part = parts[i];
+		if (part.startsWith("exp: ")) {
+			exports.push(
+				...part
+					.slice(5)
+					.split(",")
+					.map((s) => s.trim())
+					.filter(Boolean),
+			);
+		} else if (part.startsWith("dep: ")) {
+			deps.push(
+				...part
+					.slice(5)
+					.split(",")
+					.map((s) => s.trim())
+					.filter(Boolean),
+			);
+		}
+	}
+
+	return { name, purpose, exports, deps };
 }