feat: fuzzy file search with @ prefix

- Type @ to fuzzy-search files/folders across project
- Respects .gitignore and skips hidden files
- Pure Node.js implementation using readdir with withFileTypes
- No external dependencies (fd/find) required
- Also optimized Tab completion to use withFileTypes instead of statSync

Based on PR #60 by @fightbulc, reimplemented for performance.

packages/tui/package.json

@@ -41,6 +41,7 @@
 		"chalk": "^5.5.0",
 		"marked": "^15.0.12",
 		"mime-types": "^3.0.1",
+		"minimatch": "^10.1.1",
 		"string-width": "^8.1.0"
 	},
 	"devDependencies": {