cleanup: remove unnecessary files and dependencies

- Remove duplicate database files (database.sqlite, database/jaryo.db)
- Remove test files (test-login.html)
- Remove redundant deployment scripts (deploy.sh, start-simple.bat)
- Remove vercel dev dependency and fix security vulnerabilities
- Clean up project structure for better maintainability

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -18,9 +18,6 @@
     "sqlite3": "^5.1.6",
     "uuid": "^9.0.1"
   },
-  "devDependencies": {
-    "vercel": "^32.0.0"
-  },
   "keywords": [
     "file-manager",
     "admin"