feat: guided light meditation + Edge TTS neural voice audio

- Add continuous guided light-body-scan meditation (16 segments, 97% coverage)
- Edge TTS API endpoint with Xiaoxiao neural voice at -40% rate
- Pre-generated chime WAVs and guidance MP3s in public/audio/
- Mute toggle in practice page, sequenced non-overlapping audio
- Fix middleware to serve /audio and /api/audio/tts without auth
- All LLM output localized to Chinese; fix blank home/settings pages
- DeepSeek API compat: json_object, increased max_tokens
- Analytics, cron reminders, onboarding flow fixes

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dictionaries/en.ts

@@ -93,6 +93,10 @@ const en: Dict = {
       begin: "Begin practice",
       why_prefix: "", // unused in English, kept for key parity with zh
     },
+
+    session: {
+      completed: "Practice complete! Keep it going.",
+    },
   },
 
   // -----------------------------------------------------------------------
@@ -185,6 +189,10 @@ const en: Dict = {
     finish_early: "Finish early",
     complete: "Practice complete",
     reflect: "Reflect on your practice",
+    mute: "Mute",
+    unmute: "Unmute",
+    mid_guidance: "Stay focused, you're doing well.",
+    end_guidance: "Practice complete. Take a moment to reflect.",
   },
 
   // -----------------------------------------------------------------------