feat: add SQLite database and projects table schema

- Install better-sqlite3 package for persistent storage
- Create database service with projects table schema
- Add indexes on deletedAt and name for efficient queries
- Support soft-delete with deletedAt timestamp
- Export database instance for use in server.js

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -16,6 +16,7 @@
     "@xterm/addon-web-links": "^0.12.0",
     "@xterm/xterm": "^6.0.0",
     "bcryptjs": "^3.0.3",
+    "better-sqlite3": "^12.6.2",
     "cookie-parser": "^1.4.7",
     "express": "^4.22.1",
     "express-session": "^1.18.2",