Audio feedback update

Added the following files :

- AudioCue.kt
- AudioFeedbackEngine
- AudioFeedbackSettings

Edited files :

- BowlingCameraActivity (added the triggerAudiofeedback function)

app/src/main/java/com/example/jnicpp/bowling/AudioFeedbackSettings.kt

@@ -0,0 +1,54 @@
+/**
+ * @file AudioFeedbackSettings.kt
+ * @brief SharedPreferences-backed user preferences for audio coaching feedback.
+ */
+package com.example.jnicpp.bowling
+
+import android.content.Context
+
+/**
+ * @brief Persisted audio-feedback preferences: mute toggle and volume level.
+ *
+ * Reads and writes go straight to SharedPreferences via `apply()` (async
+ * disk write), so property access is safe on any thread. [AudioFeedbackEngine]
+ * reads these on every [AudioFeedbackEngine.speak] call, meaning a mute or
+ * volume change takes effect for the very next cue without restarting the engine.
+ *
+ * Instantiate once per app session (e.g. in the Activity that owns
+ * [AudioFeedbackEngine]) and pass the same instance wherever settings need
+ * to be read or written.
+ */
+class AudioFeedbackSettings(context: Context) {
+
+    private val prefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
+
+    /**
+     * @brief Whether all audio feedback is silenced.
+     *
+     * When true, [AudioFeedbackEngine.speak] is a no-op regardless of
+     * [volume]. Defaults to false (audio on).
+     */
+    var isMuted: Boolean
+        get() = prefs.getBoolean(KEY_MUTED, false)
+        set(value) { prefs.edit().putBoolean(KEY_MUTED, value).apply() }
+
+    /**
+     * @brief Playback volume in [0.0, 1.0].
+     *
+     * Maps directly to TTS's `KEY_PARAM_VOLUME`; 1.0 means full stream
+     * volume, 0.0 is silent (distinct from [isMuted] -- a volume of 0.0
+     * with mute off still triggers TTS but produces no audible output,
+     * whereas mute suppresses the TTS call entirely). Defaults to 1.0.
+     * Values outside [0.0, 1.0] are clamped on write.
+     */
+    var volume: Float
+        get() = prefs.getFloat(KEY_VOLUME, DEFAULT_VOLUME)
+        set(value) { prefs.edit().putFloat(KEY_VOLUME, value.coerceIn(0f, 1f)).apply() }
+
+    companion object {
+        private const val PREFS_NAME     = "audio_feedback_prefs"
+        private const val KEY_MUTED      = "muted"
+        private const val KEY_VOLUME     = "volume"
+        private const val DEFAULT_VOLUME = 1.0f
+    }
+}