Console: prevent repeated snapshot remounts and add localized fast live view

[2160039878-cyber]

Problem\n\nThe local console has three usability issues in real use:\n\n1. When /events repeatedly emits snapshot_required (for example during a publication gap), the browser handler closes, re-snapshots, remounts the active route, and immediately reconnects. A repeated gap therefore causes an unbounded remount loop; forms visibly flash and cannot be used.\n2. /live waits for an aggregate, a thread ranking, and a time-series query before rendering anything useful. On a large local index this makes the first view unnecessarily slow.\n3. The console is English-only even though it is a local end-user interface.\n\n## Proposed change\n\n- Allow one clean re-snapshot/reopen after snapshot_required; if the fresh source also reports a gap, stop watching and preserve the current page instead of remounting forever.\n- Render the live summary first; make trend/ranking data explicit on-demand detail and cache it for the current committed generation.\n- Add a persisted English / Simplified Chinese selector that localizes the console shell and user-facing labels while preserving API values and routes.\n\n## Reproduction\n\n1. Open /explore with live watching enabled.\n2. Make /events return snapshot_required twice in succession.\n3. Observe repeated route remounts and a flashing/empty form.\n\n## Acceptance criteria\n\n- A persistent gap results in at most one route remount and no reconnect loop.\n- Live summary appears without waiting for ranking/time-series queries.\n- Detail data remains available on demand and cache entries are scoped to the committed generation.\n- Language choice persists locally and default English behavior remains unchanged.