chore: add sproutclaw git workflow and track local extensions

Document main/upstream-sync/feature branch strategy, add sync/push
scripts, track .pi/agent extensions and webui in git, and disable
startup changelog via showChangelogOnStartup.

Co-authored-by: Cursor <cursoragent@cursor.com>

.pi/agent/extensions/webui/frontend/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "sproutclaw-webui-frontend",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "generate-icons": "node scripts/generate-icons.mjs",
+    "dev": "vite",
+    "build": "npm run generate-icons && tsc -b && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "highlight.js": "^11.11.1",
+    "marked": "^15.0.12",
+    "react": "^19.1.0",
+    "react-dom": "^19.1.0",
+    "react-router-dom": "^7.6.2"
+  },
+  "devDependencies": {
+    "@types/react": "^19.1.8",
+    "@types/react-dom": "^19.1.6",
+    "@vitejs/plugin-react": "^4.5.2",
+    "sharp": "^0.34.2",
+    "typescript": "^5.8.3",
+    "vite": "^6.3.5",
+    "vite-plugin-pwa": "^1.0.0"
+  }
+}