fix(app): stop a dispatcher exception from killing the whole app

Ctrl+C in a Mission Control terminal tile is bound by the terminal library to
CopyAsync, which throws IndexOutOfRangeException out of XTerm's selection buffer
on some selections. It runs from an async void key handler, so the exception
reached the dispatcher unhandled and terminated the process -- every open ConPTY
session with it. Handle it instead and surface the message in the footer error
strip. Iciclecreek.Avalonia.Terminal 2.0.3 is the newest release, so there is no
upstream fix to take.

src/ClaudeDo.Localization/locales/en.json

@@ -642,7 +642,7 @@
   },
   "vm": {
     "connection": { "online": "Online", "connecting": "Connecting…", "offline": "Offline" },
-    "shell": { "restartingWorker": "Restarting worker…" },
+    "shell": { "restartingWorker": "Restarting worker…", "unexpectedError": "Unexpected error: {0}" },
     "agentStatus": { "idle": "Idle", "queued": "Queued", "running": "Running", "review": "Review", "children": "Waiting for Subtasks", "done": "Done", "failed": "Failed", "cancelled": "Cancelled" },
     "taskStatus": { "idle": "Idle", "queued": "Queued", "running": "Running", "waitingForReview": "Waiting for Review", "waitingForChildren": "Waiting for Subtasks", "done": "Done", "failed": "Failed", "cancelled": "Cancelled", "parked": "Parked", "interactive": "Interactive" },
     "planningBadge": { "active": "PLANNING", "finalized": "PLANNED" },