refactor: switch from better-sqlite3 to node:sqlite (zero dependencies)

better-sqlite3 native addon fails on Node v25. Node.js built-in SQLite
(node:sqlite) has an identical synchronous API and requires no compilation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -25,8 +25,5 @@
   "repository": {
     "type": "git",
     "url": "https://github.com/dtzp555-max/ocp"
-  },
-  "dependencies": {
-    "better-sqlite3": "^12.8.0"
   }
 }