fix(mac): prevent Option release deadlock and HUD layout storm

The hold-to-talk release path called AsyncStream.Continuation.finish()
while holding MacAudioRecorder's NSLock; onTermination re-entered the
same lock on the main thread and froze the app. Finish snapshot sinks
outside the lock and guard the audio tap once stop() begins.

The dictation HUD no longer reassigns its hosting view and forces a
synchronous relayout on every view-model tick; it uses a fixed panel
size and SwiftUI @ObservedObject refresh instead.

Adds OSGKeyboardMacTests with a regression test that fails under the
old lock re-entry pattern.

OSGKeyboardMac/MacDictationOverlayController.swift

@@ -22,7 +22,9 @@ final class MacDictationOverlayController {
     private var wasBusy = false
 
     private let bottomMargin: CGFloat = 36
-    private let fallbackSize = NSSize(width: 400, height: 52)
+    /// The pill is a fixed size, so the panel never needs to resize while the
+    /// transcript grows — see `MacDictationOverlayView.panelSize`.
+    private let panelSize = MacDictationOverlayView.panelSize
 
     // MARK: - User-draggable position (persisted across launches)
 
@@ -33,8 +35,6 @@ final class MacDictationOverlayController {
     /// pill grows / shrinks with the live transcript (symmetric resize).
     private var customCenterX: CGFloat = 0
     private var customOriginY: CGFloat = 0
-    /// The origin we last set programmatically (kept for clamping / bookkeeping).
-    private var lastProgrammaticOrigin: NSPoint?
     /// Cursor + window origin captured at the start of a manual drag, so we can
     /// follow the absolute cursor and stay immune to the window moving under it.
     private var dragCursorStart: NSPoint?
@@ -72,15 +72,11 @@ final class MacDictationOverlayController {
         }
         .store(in: &cancellables)
 
-        // Keep waveform / app name / copy fresh while visible.
-        viewModel.objectWillChange
-            .receive(on: RunLoop.main)
-            .sink { [weak self] _ in
-                guard let self, self.panel?.isVisible == true else { return }
-                self.refreshContent(viewModel: viewModel)
-                self.resizeToFit()
-            }
-            .store(in: &cancellables)
+        // Waveform / app name / copy refresh through the view's own
+        // `@ObservedObject` binding. Re-driving them from `objectWillChange`
+        // used to reassign `rootView` and force a synchronous relayout ~20×/s
+        // (the level timer's cadence), which deadlocked AppKit layout during
+        // the state storm that fires when the hold-to-talk key is released.
 
         NotificationCenter.default.publisher(for: NSApplication.didChangeScreenParametersNotification)
             .receive(on: RunLoop.main)
@@ -121,8 +117,9 @@ final class MacDictationOverlayController {
 
     private func present(viewModel: MacDictationViewModel) {
         ensurePanel(viewModel: viewModel)
+        // Once per show, not per state change: picks up an appearance or UI
+        // language switch made since the pill was last visible.
         refreshContent(viewModel: viewModel)
-        resizeToFit()
         reposition()
 
         guard let panel else { return }
@@ -144,11 +141,11 @@ final class MacDictationOverlayController {
         if panel != nil { return }
 
         let host = NSHostingView(rootView: makeRoot(viewModel: viewModel))
-        host.frame = NSRect(origin: .zero, size: fallbackSize)
+        host.frame = NSRect(origin: .zero, size: panelSize)
         hosting = host
 
         let panel = NSPanel(
-            contentRect: NSRect(origin: .zero, size: fallbackSize),
+            contentRect: NSRect(origin: .zero, size: panelSize),
             styleMask: [.borderless, .nonactivatingPanel],
             backing: .buffered,
             defer: false
@@ -188,40 +185,11 @@ final class MacDictationOverlayController {
         )
     }
 
-    private func resizeToFit() {
-        guard let panel, let hosting else { return }
-        hosting.layoutSubtreeIfNeeded()
-        let fitting = hosting.fittingSize
-        // Bounds include the 32pt horizontal transparent margin around the pill
-        // (16 per side) that gives the shadow room, so the pill body itself
-        // still spans ~300–520.
-        let width = fitting.width.isFinite && fitting.width > 1
-            ? min(max(fitting.width, 332), 552)
-            : fallbackSize.width
-        let height = fitting.height.isFinite && fitting.height > 1
-            ? max(fitting.height, fallbackSize.height)
-            : fallbackSize.height
-        var frame = panel.frame
-        // Grow / shrink around the anchor center so the pill stays put: the
-        // dragged center when custom, otherwise its current center.
-        let targetMidX = hasCustomPosition ? customCenterX : frame.midX
-        frame.size = NSSize(width: width, height: height)
-        if targetMidX.isFinite {
-            frame.origin.x = targetMidX - width / 2
-        }
-        if let visible = (NSScreen.main ?? NSScreen.screens.first)?.visibleFrame {
-            frame.origin = clampedOrigin(frame.origin, size: frame.size, in: visible)
-        }
-        lastProgrammaticOrigin = frame.origin
-        panel.setFrame(frame, display: true)
-        hosting.frame = NSRect(origin: .zero, size: frame.size)
-    }
-
     private func reposition() {
         guard let panel else { return }
         let screen = NSScreen.main ?? NSScreen.screens.first
         guard let visible = screen?.visibleFrame else { return }
-        let size = panel.frame.size
+        let size = panelSize
         // Respect the user's dragged spot; otherwise snap to bottom-center.
         let desired: NSPoint
         if hasCustomPosition {
@@ -232,9 +200,7 @@ final class MacDictationOverlayController {
                 y: visible.minY + bottomMargin
             )
         }
-        let origin = clampedOrigin(desired, size: size, in: visible)
-        lastProgrammaticOrigin = origin
-        panel.setFrameOrigin(origin)
+        panel.setFrameOrigin(clampedOrigin(desired, size: size, in: visible))
     }
 
     /// Keep the panel fully inside the screen's visible frame so a dragged /
@@ -266,9 +232,7 @@ final class MacDictationOverlayController {
         )
         let size = panel.frame.size
         let visible = (NSScreen.main ?? NSScreen.screens.first)?.visibleFrame
-        let origin = visible.map { clampedOrigin(target, size: size, in: $0) } ?? target
-        lastProgrammaticOrigin = origin
-        panel.setFrameOrigin(origin)
+        panel.setFrameOrigin(visible.map { clampedOrigin(target, size: size, in: $0) } ?? target)
     }
 
     /// Persist the dragged spot as center-X + bottom-left Y.
@@ -287,7 +251,6 @@ final class MacDictationOverlayController {
     private func resetPositionToDefault() {
         hasCustomPosition = false
         clearPersistedPosition()
-        resizeToFit()
         reposition()
     }