oauth: persist client state, simplify IPC, and refactor

connected-accounts UI

This refactor simplifies OAuth storage/IPC and updates the Electron UI
to use the new client-facing contract. OAuth state is now persisted per
provider with tokens, optional clientId, and an error string. A new oauth:getState
IPC returns only client-facing state (connected + error), and the UI renders
error/reconnect flow based on that.

  Core changes
  - Replace OAuth config with providers { tokens, clientId?, error? }
    and add zod-based migration from legacy token maps.
  - Persist Google clientId after successful OAuth and keep error state
    in repo.
  - Surface provider errors from refresh/credential failures in Google +
    Fireflies.
  - Add oauth:getState in IPC, returning client-facing config; remove
    old status wiring in the UI.

  UI changes
  - Switch renderer status checks to oauth:getState and derive connected/error
    from config.
  - Add alert dialog for account issues and update copy to “Connected
    accounts”.
  - Provide “View connected accounts” CTA that opens the Connectors popover.
  - Add shadcn alert-dialog component and Radix dependency.

  Notes
  - Adds @radix-ui/react-alert-dialog and shadcn wrapper.
  - pnpm-lock updated accordingly.

apps/x/apps/renderer/package.json

@@ -43,6 +43,7 @@
     "motion": "^12.23.26",
     "nanoid": "^5.1.6",
     "posthog-js": "^1.332.0",
+    "radix-ui": "^1.4.3",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "sonner": "^2.0.7",