Fix audio routing and update the menu

.github/workflows/ci.yml

@@ -0,0 +1,24 @@
+name: Build and safety checks
+on:
+  push:
+    branches: [main]
+  pull_request:
+permissions:
+  contents: read
+concurrency:
+  group: checks-${{ github.ref }}
+  cancel-in-progress: true
+jobs:
+  check:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-14, macos-15-intel]
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 25
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - run: ./build.sh
+      - run: ./check.sh

.gitignore

@@ -11,3 +11,7 @@ xcuserdata/
 
 # Editor / tool config
 .claude/
+
+# Local test binaries
+.checks/
+__pycache__/

App/AudioObservation.swift

@@ -0,0 +1,20 @@
+import CoreAudio
+import Foundation
+
+/// Owns the exact block and queue required to remove a CoreAudio listener.
+final class AudioObservation {
+    private let object: AudioObjectID
+    private var address: AudioObjectPropertyAddress
+    private let block: AudioObjectPropertyListenerBlock
+
+    init?(object: AudioObjectID = AudioObjectID(kAudioObjectSystemObject),
+          selector: AudioObjectPropertySelector, handler: @escaping @MainActor () -> Void) {
+        self.object = object
+        address = AudioObjectPropertyAddress(mSelector: selector,
+            mScope: kAudioObjectPropertyScopeGlobal, mElement: kAudioObjectPropertyElementMain)
+        block = { _, _ in MainActor.assumeIsolated { handler() } }
+        guard AudioObjectAddPropertyListenerBlock(object, &address, .main, block) == noErr else { return nil }
+    }
+
+    deinit { AudioObjectRemovePropertyListenerBlock(object, &address, .main, block) }
+}

App/AudioRecovery.swift

@@ -0,0 +1,44 @@
+import Foundation
+
+/// A child owns the read end of a pipe. App termination (including SIGKILL)
+/// closes the write end, waking it to restore the output without a login item.
+final class AudioRecovery {
+    private var process: Process?
+    private var input: FileHandle?
+
+    var isRunning: Bool { process?.isRunning == true }
+
+    func arm(preferredUID: String?) throws {
+        disarm()
+        guard let executable = Bundle.main.url(forAuxiliaryExecutable: "MacStereoFixRecovery") else {
+            throw CocoaError(.fileNoSuchFile)
+        }
+        let child = Process()
+        let pipe = Pipe()
+        child.executableURL = executable
+        child.arguments = [preferredUID ?? ""]
+        child.standardInput = pipe
+        child.standardOutput = FileHandle.nullDevice
+        child.standardError = FileHandle.nullDevice
+        try child.run()
+        _ = fcntl(pipe.fileHandleForWriting.fileDescriptor, F_SETNOSIGPIPE, 1)
+        process = child
+        input = pipe.fileHandleForWriting
+        // Process.run returns only after a successful exec; EOF is retained if
+        // the parent exits before the child starts reading.
+    }
+
+    func disarm() {
+        if let input {
+            try? input.write(contentsOf: Data("disarm\n".utf8))
+            try? input.close()
+        }
+        input = nil
+        process = nil
+    }
+
+    deinit {
+        // No disarm here: unexpected owner destruction must trigger recovery.
+        try? input?.close()
+    }
+}