Stream app operator state over WebSocket

[yvette-carlisle]

Summary

• switch Decodex App operator status from HTTP snapshot polling to the dashboard WebSocket stream
• merge dashboard snapshot and runActivity events in the app so lane details stay fresh
• make serve --api-only publish live local snapshots over the same dashboard WebSocket while still avoiding project polling/automation

Validation

• swift build (apps/decodex-app)
• cargo nextest run -p decodex control_plane_api_only_snapshot_does_not_tick_enabled_projects control_plane_api_only_snapshot_includes_local_active_runs operator_dashboard_websocket_sends_current_snapshot_on_connect
• cargo make fmt-rust-check
• cargo make check-vstyle-rust
• cargo make test-decodex-app-stage