feat: session rename — double-click or pencil icon to set custom session names

- Double-click session name in sidebar to rename inline
- Pencil icon on hover for discoverability
- Custom names persisted in localStorage
- Enter to confirm, Escape to cancel, blur to save
- Clear name to revert to auto-generated display name
- Search filter respects custom names
- i18n for all 8 languages

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "pinchchat",
-  "version": "1.61.0",
+  "version": "1.62.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "pinchchat",
-      "version": "1.61.0",
+      "version": "1.62.0",
       "license": "MIT",
       "dependencies": {
         "@tailwindcss/vite": "^4.1.18",