feat: rename ClawChat → PinchChat across entire project

- Update package.json name and repo URL
- Update README.md, CONTRIBUTING.md branding and links
- Update UI components (Header, Chat) display names
- Update gateway user-agent string
- Rename GitHub repo via API
- Mark FEEDBACK.md item #1 as done

package.json

@@ -1,11 +1,11 @@
 {
-  "name": "clawchat",
+  "name": "pinchchat",
   "version": "1.0.0",
   "description": "A sleek, dark-themed webchat UI for OpenClaw — monitor sessions, stream responses, and inspect tool calls in real-time.",
   "type": "module",
   "repository": {
     "type": "git",
-    "url": "https://github.com/MarlBurroW/clawchat.git"
+    "url": "https://github.com/MarlBurroW/pinchchat.git"
   },
   "license": "MIT",
   "author": "Nicolas Varrot",