Add AST extraction tests, broader ignore patterns, build dist

- ast-extract.ts: Support tree-sitter-python and tree-sitter-go grammar
  loading (pkg.language fallback)
- discover.ts: Add cache directories to default ignore (.cache, tmp,
  temp, .turbo, .parcel-cache, .eslintcache, .prettiercache)
- tests: Add TypeScript AST extraction tests (exports + imports)
- Verified on real project: media_library_viewer (196 .pi-map.md files)
  with accurate React component extraction
- Build: npm run build produces clean dist/ output

All 16 tests pass.

tests/integration.test.ts

@@ -1,5 +1,11 @@
 import { describe, it, expect, beforeEach, afterEach } from "vitest";
-import { mkdtempSync, writeFileSync, mkdirSync, rmSync, readFileSync } from "fs";
+import {
+	mkdtempSync,
+	writeFileSync,
+	mkdirSync,
+	rmSync,
+	readFileSync,
+} from "fs";
 import { join } from "path";
 import { tmpdir } from "os";
 import { initProject } from "../src/init.js";
@@ -19,10 +25,7 @@ describe("integration", () => {
 
 	it("init creates .pi-map.md files", async () => {
 		mkdirSync(join(dir, "src"));
-		writeFileSync(
-			join(dir, "src", "index.ts"),
-			`export function foo() {}\n`,
-		);
+		writeFileSync(join(dir, "src", "index.ts"), `export function foo() {}\n`);
 		await initProject(dir);
 
 		const map = readFileSync(join(dir, "src", ".pi-map.md"), "utf8");
@@ -32,14 +35,8 @@ describe("integration", () => {
 
 	it("patch updates a file entry", async () => {
 		mkdirSync(join(dir, "src"));
-		writeFileSync(
-			join(dir, "src", "index.ts"),
-			`export function foo() {}\n`,
-		);
-		writeFileSync(
-			join(dir, "src", "utils.ts"),
-			`export const bar = 1;\n`,
-		);
+		writeFileSync(join(dir, "src", "index.ts"), `export function foo() {}\n`);
+		writeFileSync(join(dir, "src", "utils.ts"), `export const bar = 1;\n`);
 		await initProject(dir);
 
 		// Modify a file
@@ -110,10 +107,15 @@ describe("integration", () => {
 		await initProject(dir);
 
 		// Change exports
-		writeFileSync(join(dir, "src", "a.ts"), `export const a = 1;\nexport const c = 3;\n`);
+		writeFileSync(
+			join(dir, "src", "a.ts"),
+			`export const a = 1;\nexport const c = 3;\n`,
+		);
 
 		const result = await validateMaps(dir);
 		expect(result.clean).toBe(false);
-		expect(result.discrepancies.some((d) => d.type === "stale-signature")).toBe(true);
+		expect(result.discrepancies.some((d) => d.type === "stale-signature")).toBe(
+			true,
+		);
 	});
 });