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.

package-lock.json

@@ -2379,6 +2379,8 @@
 		},
 		"node_modules/minimatch": {
 			"version": "10.1.1",
+			"resolved": "https://registry.npmjs.org/minimatch/-/minimatch-10.1.1.tgz",
+			"integrity": "sha512-enIvLvRAFZYXJzkCYG5RKmPfrFArdLv+R+lbQ53BmIMLIry74bjKzX6iHAm8WYamJkhSSEabrWN5D97XnKObjQ==",
 			"license": "BlueOak-1.0.0",
 			"dependencies": {
 				"@isaacs/brace-expansion": "^5.0.0"
@@ -3955,6 +3957,7 @@
 				"chalk": "^5.5.0",
 				"marked": "^15.0.12",
 				"mime-types": "^3.0.1",
+				"minimatch": "^10.1.1",
 				"string-width": "^8.1.0"
 			},
 			"devDependencies": {