fix: add repository.url to server/package.json for npm provenance

Author: ZengLiangYi

server/package.json

@@ -2,6 +2,10 @@
   "name": "chatcrystal",
   "version": "0.2.5",
   "private": false,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/ZengLiangYi/ChatCrystal"
+  },
   "description": "Turn your AI conversations into searchable knowledge — supports Claude Code, Cursor, Codex CLI",
   "keywords": [
     "claude",