Overview

This change tightens coordination between BLE scanning and TCP/network scanning in the Meshtastic connections feature. It enforces mutual exclusion so only one discovery mode runs at a time, prevents lifecycle-driven BLE scan stop/start cycling, keeps scan state reliable across async cancellation, and stops discovery immediately when initiating a connection. The result is a more stable scan experience without blocking users from scanning for another transport while already connected.

This should land before the related Wi-Fi unavailable banner PR (#5892), because that follow-up uses isNetworkScanning as the user-intent gate for when the recovery banner should appear.

Key changes

Fixes

• Enforced mutual exclusion between BLE and network scans:
  • Starting a BLE scan cancels any active network scan first.
  • Starting a network scan cancels any active BLE scan first.
• Fixed lifecycle-driven BLE scan cycling:
  • BLE auto-start is keyed to screen lifecycle entry instead of bleAutoScan preference writes.
  • Network auto-start is keyed to local-network permission state so permission-grant auto-start still works without restarting on preference writes.
• Improved async lifecycle cleanup for BLE:
  • Added a scan generation guard so only the latest BLE scan’s cleanup path can clear _isBleScanning.
  • Prevents stale cancellation cleanup from corrupting the state of a newly-started scan.
• Updated scan stopping during connection flows:
  • onSelected() stops all active scans before connection, bonding, USB permission, mock, or replay setup.
  • connectToManualAddress() applies the same stop-before-connect invariant for manually-entered TCP addresses.
• Preserved flexible scan policy:
  • Scanning is allowed in Disconnected, Connecting, Connected, and DeviceSleep.
  • This keeps valid workflows like scanning for TCP nodes while connected over BLE.

Features

• Reworked auto-scan toggle and persistence semantics to align stored intent with actual runtime activation:
  • toggleBleScan() and toggleNetworkScan() persist auto-scan intent only when enabling actually starts the corresponding scan.
  • Enabling one scan type clears the opposite auto-scan preference to match the runtime mutual-exclusion invariant.
  • persistNetworkAutoScanIntent(true) also clears bleAutoScan, covering the permission-deferred network scan path.

Refactors

• Removed local Compose state collection for bleAutoScan and networkAutoScan in ConnectionsScreen; lifecycle effects now read current StateFlow values directly.
• Removed the TCP_DEVICE_PREFIX import from ConnectionsScreen by routing manual TCP entry through ScannerViewModel.connectToManualAddress(fullAddress).
• Added small scan lifecycle helpers and public-method documentation around scan state, auto-scan preferences, and connection entry points.
• Updated the scanner test harness so BLE scan mocks default to a non-completing flow, matching a real active scan more closely.

Testing

• Expanded ScannerViewModelTest coverage for:
  • BLE/network mutual cancellation.
  • scan activation across connection states.
  • connection-state transitions not cancelling active scans.
  • auto-scan preference persistence and opposite-pref clearing.
  • persistNetworkAutoScanIntent(true) clearing BLE auto-scan.
  • onSelected() stopping active scans before device/address changes.
  • connectToManualAddress() stopping active network scans before connecting.
• Updated ScannerViewModelHarness BLE scanner mock behavior:
  • Uses a default non-completing Flow with awaitCancellation() to prevent premature scan-state cleanup under UnconfinedTestDispatcher.
  • Adds Mokkery argument matching support for the default BLE scanner stub.

Breaking changes / migration

No breaking API or user-facing migration steps are required. Changes are internal to connection scan lifecycle coordination and related test harness behavior.