feat(typescript): convert 4 missing utilities to TypeScript

- claude-dir-installer.ts: copy .claude/ from package (~300 LOC)
- claude-symlink-manager.ts: selective symlinks to ~/.claude/ (~310 LOC)
- progress-indicator.ts: CLI spinners/progress display (~120 LOC)
- update-checker.ts: version update notifications (~250 LOC)

All strict TypeScript, no any types, cross-platform compatible.
39/39 tests pass.

package.json

@@ -50,7 +50,7 @@
   "scripts": {
     "build": "tsc && node scripts/add-shebang.js",
     "build:watch": "tsc --watch",
-    "prebuild": "rm -rf dist",
+    "prebuild": "rm -rf dist tsconfig.tsbuildinfo",
     "test": "npm run build && npm run test:all",
     "test:all": "npm run test:unit && npm run test:npm",
     "test:unit": "npx mocha tests/shared/unit/**/*.test.js --timeout 5000",