#243 Improve Core reconnect feedback

Summary

• replace floating reconnect indicator with graduated, layout-integrated Core status feedback
• distinguish confirmed network outages and preserve cached device metadata during reconnects
• add accessible recovery announcements, regression coverage, and translations for every supported locale

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Summary by cubic

Integrates an in-layout ConnectionStatusBar that replaces the floating reconnect pill and provides timed, prioritized feedback for connects, reconnects, Core outages, and offline network. Previously a floating “Connecting…/Reconnecting…” pill was always shown; now sub‑second reconnects stay hidden, prolonged issues escalate, and Home/Settings rely on contextual cards.

• Behavior and timing: reveal after 1s; escalate to “Core unavailable” after 10s; prioritize “No network connection”; announce “Connected to Core” for 3s only if a visible issue was shown before; clear the recovery notice if the connection drops again or pairing becomes required; suppress recovery for hidden quick reconnects.

• State handling: track browser navigator.onLine and native @capacitor/network to set networkAvailable, start/clear timing via beginConnectionIssue/clearConnectionIssue, and immediately reconnect when online; suppress generic status when pairing is required or the Core encryption version is unsupported.

• Data retention: keep cached Core version/platform and client capabilities during same‑device reconnect refresh failures; on device switch, clear prior‑device metadata if the refresh fails; keep inbox messages/modal open until a reconnect refresh replaces them.

• Implementation: add useConnectionPresentation to drive presentation; render ConnectionStatusBar above BottomNav with safe‑area padding and a Settings link when unavailable; include a screen‑reader‑only live announcement on all routes and hide the visual bar on Home/Settings; update docs, tests, and translations to use connection.connectingToCore, connection.reconnectingToCore, connection.coreUnavailable, connection.networkUnavailable, and connection.restored.

• Migration

  • Remove any usages of ReconnectingIndicator and rely on ConnectionStatusBar or contextual cards.
  • Update string keys to the new connection.*ToCore and availability keys.

Summary by CodeRabbit

• New Features

  • Added contextual connection status banners for connecting, reconnecting, service unavailability, network loss, and restored connectivity.
  • Added a Settings link when connection issues require attention.
  • Improved connection messaging across Home and Settings, with brief restored-status feedback.
  • Added localized connection-status messages across supported languages.

• Bug Fixes

  • Improved reconnection behavior and network-state detection.
  • Preserved available connection details during temporary refresh failures.
  • Respect reduced-motion preferences for connection indicators.