Voice: fix audio-session leak causing insufficientPriority (561017449)

Decoded the device error: NSOSStatusErrorDomain 561017449 = '!pri' =
AVAudioSession insufficientPriority — the mic was denied because a session was
left active (which also blocks the keyboard's own dictation).

Root cause: the early-return guards (recognizer unavailable / invalid format) ran
AFTER setActive(true) but never deactivated, leaking an active session. Also the
.measurement + .duckOthers config is more prone to priority denials.

Fixes:
- Deactivate any stale active session before starting.
- Use .record / .default (least-exclusive recording config).
- stopEngine() now always releases the session (no early-out), and the bailout
  guards call it so the session is never left active.
- Map 561017449 to an actionable message (close other audio apps / restart).

Device-specific; not reproducible on the sim (blocks at the permission dialog).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

KisaniCal/Managers/SpeechRecognizer.swift

@@ -69,12 +69,19 @@ final class SpeechRecognizer: ObservableObject {
 
         do {
             let session = AVAudioSession.sharedInstance()
-            try session.setCategory(.playAndRecord, mode: .measurement, options: [.duckOthers, .defaultToSpeaker])
+            // Release any session left active by a prior attempt — a stuck-active
+            // session causes error 561017449 ('!pri', insufficientPriority) and can
+            // also block the keyboard's own dictation from grabbing the mic.
+            try? session.setActive(false, options: .notifyOthersOnDeactivation)
+            // Plain .record/.default is the least-exclusive recording config; the
+            // earlier .measurement + .duckOthers combo is more prone to priority denials.
+            try session.setCategory(.record, mode: .default)
             try session.setActive(true, options: .notifyOthersOnDeactivation)
 
             guard let recognizer, recognizer.isAvailable else {
                 error = "Speech recognition is not available right now."
                 print("[VOICE] Recognizer unavailable")
+                stopEngine()   // release the session we just activated
                 return
             }
 
@@ -86,6 +93,7 @@ final class SpeechRecognizer: ObservableObject {
             guard fmt.sampleRate > 0, fmt.channelCount > 0 else {
                 error = "No microphone input available on this device."
                 print("[VOICE] Invalid input format: \(fmt)")
+                stopEngine()   // release the session we just activated
                 return
             }
 
@@ -125,7 +133,13 @@ final class SpeechRecognizer: ObservableObject {
 
         } catch {
             let ns = error as NSError
-            self.error = "Could not start recording. (\(ns.domain) \(ns.code))"
+            // 561017449 = '!pri' = AVAudioSession insufficientPriority: another app/
+            // process holds the mic, or the audio system is in a stuck state.
+            if ns.code == 561017449 {
+                self.error = "Microphone is busy. Close other audio apps (calls, Voice Memos), then try again. If it persists, restart your phone."
+            } else {
+                self.error = "Could not start recording. (\(ns.code))"
+            }
             print("[VOICE] Engine start failed: \(ns.domain) \(ns.code) — \(error.localizedDescription)")
             stopEngine()
         }
@@ -137,14 +151,15 @@ final class SpeechRecognizer: ObservableObject {
     }
 
     private func stopEngine() {
-        guard audioEngine.isRunning || task != nil else { return }
-        audioEngine.stop()
+        if audioEngine.isRunning { audioEngine.stop() }
         audioEngine.inputNode.removeTap(onBus: 0)
         request?.endAudio()
         task?.finish()
         request = nil
         task = nil
         isRecording = false
+        // Always release the audio session, even on a failed/partial start — a
+        // session left active denies the mic to us and to keyboard dictation.
         try? AVAudioSession.sharedInstance().setActive(false, options: .notifyOthersOnDeactivation)
     }