fix: address coderabbit review (concurrent stream, collapsed label, unified select, test quality)

- useCameraDevices: remove getUserMedia label probe to avoid conflict with
  useScreenRecorder acquiring the real stream; use enumerateDevices only and
  fall back to 'Camera <id>' for unlabeled devices; gate effect on enabled flag
- LaunchWindow: fix selectedCameraLabel to reflect loading/error/empty states
  in the collapsed view (was always showing 'Default Camera')
- LaunchWindow: unify webcam <select> to a single always-mounted element
  (sr-only when unavailable); mirrors the mic selector pattern
- useCameraDevices.test.ts: re-seed mockGetUserMedia in beforeEach after
  vi.resetAllMocks(); update permission test to assert fallback label behavior

src/components/launch/LaunchWindow.tsx

@@ -120,9 +120,14 @@ export function LaunchWindow() {
 	const selectedMicLabel =
 		micDevices.find((d) => d.deviceId === (microphoneDeviceId || selectedMicId))?.label ||
 		t("audio.defaultMicrophone");
-	const selectedCameraLabel =
-		cameraDevices.find((d) => d.deviceId === (webcamDeviceId || selectedCameraId))?.label ||
-		t("webcam.defaultCamera");
+	const selectedCameraLabel = isCameraDevicesLoading
+		? t("webcam.searching")
+		: cameraDevicesError
+			? t("webcam.unavailable")
+			: cameraDevices.length === 0
+				? t("webcam.noneFound")
+				: cameraDevices.find((d) => d.deviceId === (webcamDeviceId || selectedCameraId))?.label ||
+					t("webcam.defaultCamera");
 
 	const { level } = useAudioLevelMeter({
 		enabled: showMicControls,
@@ -444,7 +449,7 @@ export function LaunchWindow() {
 					className={`flex items-center gap-0.5 rounded-full p-2 transition-colors duration-150 ${styles.electronNoDrag} ${
 						recording ? "animate-record-pulse bg-red-500/10" : "bg-white/5 hover:bg-white/[0.08]"
 					}`}
-					onClick={hasSelectedSource ? toggleRecording : openSourceSelector}
+					onClick={toggleRecording}
 					disabled={!hasSelectedSource && !recording}
 					style={{ flex: "0 0 auto" }}
 				>