feat(ipuaro): implement indexer module (v0.3.0)

Add complete indexer infrastructure:
- FileScanner: recursive scanning with gitignore support
- ASTParser: tree-sitter based TS/JS/TSX/JSX parsing
- MetaAnalyzer: complexity metrics, dependency analysis
- IndexBuilder: symbol index and dependency graph
- Watchdog: file watching with chokidar and debouncing

321 tests, 96.38% coverage

packages/ipuaro/tests/fixtures/sample-project/src/index.ts

@@ -0,0 +1,3 @@
+export function main(): void {
+    console.log("Hello")
+}