Harden PTT audio and the 1.7.1 release (#1423)

Centralize PTT and voice audio-session ownership, harden courier/bridge/outbox delivery and recovery, correct location and delivery-state races, add privacy/release metadata, and ship reproducible universal Arti slices with Release CI coverage.

Validated by the full iOS suite, repeated audio/fragment/performance regressions, BitFoundation tests, strict lint and dead-code analysis, universal iOS Release builds, and iOS/macOS archives.

bitchat/App/NearbyNotesCounter.swift

@@ -27,6 +27,7 @@ final class NearbyNotesCounter: ObservableObject {
     private var manager: LocationNotesManager?
     private var managerCancellable: AnyCancellable?
     private var channelsCancellable: AnyCancellable?
+    private var permissionCancellable: AnyCancellable?
     private var settingCancellable: AnyCancellable?
     private var activeHolders = 0
     private let locationManager: LocationChannelManager
@@ -73,6 +74,13 @@ final class NearbyNotesCounter: ObservableObject {
         channelsCancellable = locationManager.$availableChannels
             .receive(on: DispatchQueue.main)
             .sink { [weak self] _ in self?.retarget() }
+        // CoreLocation can revoke authorization while the view remains
+        // mounted. `availableChannels` deliberately retains its last value,
+        // so permission must be an independent invalidation signal or the
+        // building REQ survives on stale coordinates.
+        permissionCancellable = locationManager.$permissionState
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] _ in self?.retarget() }
         // The app-info kill switch must take effect immediately, not on the
         // next location change or remount.
         settingCancellable = NotificationCenter.default
@@ -86,6 +94,7 @@ final class NearbyNotesCounter: ObservableObject {
         activeHolders = max(0, activeHolders - 1)
         guard activeHolders == 0 else { return }
         channelsCancellable = nil
+        permissionCancellable = nil
         settingCancellable = nil
         managerCancellable = nil
         releaseManager(manager)