Consolidate engine docs and naming

public/js/sentence-queue-module.js

@@ -753,7 +753,7 @@ class SentenceQueueModule extends BaseModule {
         if (this.lastContinueAt >= (sentence.playbackStartedAt || 0)) {
             return false;
         }
-        if (this.sentenceQueue.length <= 1 && this.inputMode === 'choice') {
+        if (this.inputMode === 'choice') {
             return false;
         }
         return this.sentenceQueue.length > 1;

public/js/tts-factory-module.js

@@ -700,18 +700,23 @@ class TTSFactoryModule extends BaseModule {
         const persistenceManager = this.getModule('persistence-manager');
         if (persistenceManager) {
             persistenceManager.updatePreference('tts', 'preferred_handler', id);
-            this.voice = persistenceManager.getPreference('tts', 'voice', this.voice || '');
+            const providerVoice = persistenceManager.getPreference('tts', `${id}_voice`, '');
+            const genericVoice = persistenceManager.getPreference('tts', 'voice', this.voice || '');
+            this.voice = providerVoice || genericVoice || '';
             this.language = String(this.getModule('game-config')?.getLocale?.() || this.language || 'en_US').replace('_', '-').toLowerCase();
             this.speed = persistenceManager.getPreference('tts', 'speed', this.speed || 1.0);
         }
 
         const handler = this.handlers[id];
         if (handler && typeof handler.setVoiceOptions === 'function') {
-            handler.setVoiceOptions({
-                voice: this.voice,
+            const voiceOptions = {
                 speed: this.speed,
                 language: this.language
-            });
+            };
+            if (this.voice) {
+                voiceOptions.voice = this.voice;
+            }
+            handler.setVoiceOptions(voiceOptions);
         }
         
         // Dispatch events