[Cloud Service] Route flow: login -> personal dashboard + sync panels

[jacksonw111]

Goal

Finalize end-user flow and feature wiring.

Scope

• Ensure authenticated users are redirected into personal dashboard after login/signup
• Dashboard includes bookmark sync and note sync panels
• Add admin panel controls visible only to admin users
• Ensure RPC integrations handle loading/error/success states

Acceptance Criteria

• Login/signup success always lands on dashboard
• Dashboard reflects per-user sync state
• Admin panel hidden for non-admin users
• Typecheck and build pass