feat(plugins): add package.json and openclaw.plugin.json for OpenClaw compatibility

- Add package.json with openclaw.extensions field for all three plugins
- Add openclaw.plugin.json manifest files
- Plugins: zclaw-chinese-models, zclaw-feishu, zclaw-ui

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

plugins/zclaw-ui/openclaw.plugin.json

@@ -0,0 +1,8 @@
+{
+  "id": "zclaw-ui",
+  "name": "ZCLAW UI Extensions",
+  "version": "0.1.0",
+  "description": "Custom Gateway RPC methods for ZCLAW Tauri desktop UI",
+  "author": "ZCLAW",
+  "entry": "index.ts"
+}