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>

src/lib/analytics.ts

@@ -0,0 +1,21 @@
+import { prisma } from "@/lib/prisma";
+
+type EventName = "session_completed" | "task_generated" | "onboarding_completed";
+
+export async function logEvent(
+  userId: string,
+  event: EventName,
+  metadata: Record<string, unknown> = {}
+): Promise<void> {
+  try {
+    await prisma.analyticsEvent.create({
+      data: {
+        userId,
+        event,
+        metadata: JSON.stringify(metadata),
+      },
+    });
+  } catch (err) {
+    console.error("[analytics] Failed to log event:", event, err);
+  }
+}