refactor(ui): remove the stale-worker banner

The banner compared the running worker's build SHA against the
selected list's HEAD via a git ancestor check on every list switch
and reconnect. It added a git-rev-parse MSBuild target, a hub call,
and a poll loop for a corner case that hasn't come up in practice —
not worth the moving parts.

src/ClaudeDo.Localization/locales/en.json

@@ -720,9 +720,6 @@
       "updateNow": "Update now",
       "dismiss": "Dismiss"
     },
-    "staleWorker": {
-      "message": "The worker is running an older build than this repo's merged main — restart it so your merged changes take effect."
-    },
     "externalMerge": {
       "banner": "A Claude session is resolving a merge conflict — don't edit files in the repository.",
       "open": "Open resolver"