RankoPins Flow Automator v4.3.5

Fixes the bridge state shown as:
  "Local bridge is running on port 8712, but no Flow extension is connected yet."

Changes:
- Default bridge port for this paired build is 8712.
- Saving a different bridge port immediately closes the old/connecting socket and reconnects on the new port.
- background.js listens for storage changes and applies bridge settings without an extension reload.
- The open Flow content script wakes the MV3 service worker every 8 seconds and triggers reconnect if needed.
- The extension sends a harmless application heartbeat over an open RankoPins WebSocket every 15 seconds so Chrome does not silently suspend the bridge worker.
- GET_BRIDGE_STATUS now reports configured port, connection state, and last error for easier diagnosis.
- Previous no-ratio, no-foreground-flash, and trusted background Generate-click fixes are retained.
