fix: release the playback slot when a note is paused

pause() left activeController set, so the slot meant "a row was played at
some point" rather than "audio is audible". Any reader of
hasActivePlayback — the swipe-to-leave policy above all — kept seeing
playback after the user paused, until the row disappeared or something
called stop().

A paused note has nothing to yield to the next playback, so it releases
the slot. hasActivePlayback becomes stored and published, so a view can
react to it rather than sample it once.

bitchat/Features/voice/VoiceNotePlaybackController.swift

@@ -113,6 +113,11 @@ final class VoiceNotePlaybackController: NSObject, ObservableObject, AVAudioPlay
         updateProgress()
         isPlaying = false
         releaseSession()
+        // The slot means "audio is audible", not "a row is selected": a paused
+        // note has nothing to yield to the next playback, and readers of
+        // `hasActivePlayback` would otherwise see playback that stopped being
+        // heard when the user paused it.
+        exclusivity.deactivate(self)
     }
 
     func stop() {
@@ -296,7 +301,7 @@ extension VoiceNotePlaybackController: ExclusivePlayback {
 }
 
 /// Ensures only one voice playback (note or live burst) runs at a time.
-final class VoiceNotePlaybackCoordinator {
+final class VoiceNotePlaybackCoordinator: ObservableObject {
     static let shared = VoiceNotePlaybackCoordinator()
 
     struct Reservation: Equatable {
@@ -339,6 +344,7 @@ final class VoiceNotePlaybackCoordinator {
         }
         activeController?.pauseForExclusivity()
         activeController = controller
+        hasActivePlayback = true
         return true
     }
 
@@ -347,9 +353,11 @@ final class VoiceNotePlaybackCoordinator {
     /// Read by the private-chat swipe-to-leave gesture, which stands down while
     /// a voice note is audible so a waveform seek is not starved by the
     /// high-priority ancestor drag. See `PrivateChatSwipeToLeavePolicy`.
-    var hasActivePlayback: Bool {
-        activeController != nil
-    }
+    ///
+    /// Published rather than computed so a view can drop the gesture for the
+    /// duration: a gesture that is armed at all starves its descendants, so
+    /// reading this only once the drag ends comes too late for the seek.
+    @Published private(set) var hasActivePlayback: Bool = false
 
     func isCurrent(_ reservation: Reservation, for controller: any ExclusivePlayback) -> Bool {
         latestReservation == reservation && latestReservedController === controller
@@ -358,6 +366,7 @@ final class VoiceNotePlaybackCoordinator {
     func deactivate(_ controller: any ExclusivePlayback) {
         if activeController === controller {
             activeController = nil
+            hasActivePlayback = false
         }
         if latestReservedController === controller {
             latestReservedController = nil

bitchatTests/PrivateChatSwipeToLeavePolicyTests.swift

@@ -8,6 +8,7 @@
 
 import Testing
 import CoreGraphics
+import Foundation
 @testable import bitchat
 
 /// A stand-in for the playback slot holder. The coordinator only needs identity
@@ -136,6 +137,42 @@ struct VoiceNotePlaybackCoordinatorActivityTests {
         #expect(coordinator.hasActivePlayback)
     }
 
+    @Test("a controller that pauses releases the slot")
+    func pauseReleasesSlot() throws {
+        // The slot means audible playback. A paused note holds nothing, and
+        // leaving it in place kept the leave gesture suppressed for the rest
+        // of the row's life.
+        let coordinator = VoiceNotePlaybackCoordinator()
+        let url = try Self.makeSilentVoiceNote()
+        defer { try? FileManager.default.removeItem(at: url) }
+        let controller = VoiceNotePlaybackController(url: url, exclusivity: coordinator)
+
+        controller.play()
+        #expect(coordinator.hasActivePlayback)
+
+        controller.pause()
+        #expect(!coordinator.hasActivePlayback)
+    }
+
+    /// A one-frame WAV: enough for AVAudioPlayer to prepare and start.
+    private static func makeSilentVoiceNote() throws -> URL {
+        let url = FileManager.default.temporaryDirectory
+            .appendingPathComponent("swipe-policy-\(UUID().uuidString).wav")
+        var data = Data()
+        func append(_ string: String) { data.append(contentsOf: Array(string.utf8)) }
+        func append(_ value: UInt32) { withUnsafeBytes(of: value.littleEndian) { data.append(contentsOf: $0) } }
+        func append(_ value: UInt16) { withUnsafeBytes(of: value.littleEndian) { data.append(contentsOf: $0) } }
+        let frames: UInt32 = 8_000            // one second at 8 kHz, 16-bit mono
+        let dataBytes = frames * 2
+        append("RIFF"); append(36 + dataBytes); append("WAVE")
+        append("fmt "); append(UInt32(16)); append(UInt16(1)); append(UInt16(1))
+        append(UInt32(8_000)); append(UInt32(16_000)); append(UInt16(2)); append(UInt16(16))
+        append("data"); append(dataBytes)
+        data.append(Data(repeating: 0, count: Int(dataBytes)))
+        try data.write(to: url)
+        return url
+    }
+
     @Test("taking over the slot pauses the previous holder and stays active")
     func takeoverKeepsPlaybackActive() {
         let coordinator = VoiceNotePlaybackCoordinator()