feat: rich AST extraction with classes, methods, calls, and raises

- Upgrade tree-sitter to 0.22.4 with compatible grammar versions
- Add Python support via tree-sitter-python@0.23.6
- Add Go support via tree-sitter-go@0.23.4
- Extract class hierarchies with method signatures (params, returns)
- Extract call graphs including external library calls
- Extract exception raises (ValueError, Error, etc)
- Extract top-level functions with full signatures
- Encode rich AST data into compact markdown format:
  class:Name, method:name(params)→return, call:..., raise:...
- Deduplicate nested call chains (db.query vs db.query().where())
- Filter out simple export names when rich func/class entries exist
- All 55 tests passing

tests/llm-cache.test.ts

@@ -26,7 +26,11 @@ describe("llm-cache", () => {
 	});
 
 	it("stores and retrieves cached results", () => {
-		setCached("abc123", "PURPOSE: test\nDEPS: none\nCONCEPTS: none", TEST_CACHE_DIR);
+		setCached(
+			"abc123",
+			"PURPOSE: test\nDEPS: none\nCONCEPTS: none",
+			TEST_CACHE_DIR,
+		);
 		const result = getCached("abc123", TEST_CACHE_DIR);
 		expect(result).toBe("PURPOSE: test\nDEPS: none\nCONCEPTS: none");
 	});