feat: use mnemonic-id for worktree names

Replace prompt-based slugifying with mnemonic-id package for generating
human-readable worktree names like "hungry-hippo". Names are generated
when the worktree toggle is enabled rather than derived from the prompt.

package-lock.json

@@ -15952,6 +15952,12 @@
         "node": ">=10"
       }
     },
+    "node_modules/mnemonic-id": {
+      "version": "3.2.7",
+      "resolved": "https://registry.npmjs.org/mnemonic-id/-/mnemonic-id-3.2.7.tgz",
+      "integrity": "sha512-kysx9gAGbvrzuFYxKkcRjnsg/NK61ovJOV4F1cHTRl9T5leg+bo6WI0pWIvOFh1Z/yDL0cjA5R3EEGPPLDv/XA==",
+      "license": "MIT"
+    },
     "node_modules/moment": {
       "version": "2.30.1",
       "resolved": "https://registry.npmjs.org/moment/-/moment-2.30.1.tgz",
@@ -21275,6 +21281,7 @@
         "expo-updates": "~29.0.12",
         "expo-web-browser": "~15.0.8",
         "lucide-react-native": "^0.546.0",
+        "mnemonic-id": "^3.2.7",
         "react": "19.1.0",
         "react-dom": "19.1.0",
         "react-native": "^0.81.5",
@@ -21335,6 +21342,7 @@
         "dotenv": "^17.2.3",
         "express": "^4.18.2",
         "express-basic-auth": "^1.2.1",
+        "mnemonic-id": "^3.2.7",
         "openai": "^4.20.0",
         "playwright": "^1.56.1",
         "tiny-invariant": "^1.3.3",