fix(minimax): correct API payload and add TTS debug logging

- Fix model name: speech-2.8-hd -> speech-02-hd
- Fix bitrate: 128 -> 128000 bps
- Add channel, speed, pitch, vol to voice/audio settings
- Handle binary audio response (Content-Type: audio/*)
- Fallback audio field lookup: data.data.audio || data.audio
- Add background job log: ttsProvider + hasMinimaxKey
- Log full FFmpeg request body (text truncated, key masked)

server/routes/reels.ts

@@ -614,9 +614,13 @@ async function processReelBackground(
             const minimaxCfg = await storage.getMinimaxConfig(userId);
             if (minimaxCfg?.apiKey) {
                 minimaxApiKeyBg = minimaxCfg.apiKey;
+            } else {
+                console.error('❌ [Background] Minimax API key not found in DB for user:', userId);
             }
         }
 
+        console.log('🔊 [Background] TTS config:', { ttsEnabled, ttsProvider, ttsVoice, hasMinimaxKey: !!minimaxApiKeyBg });
+
         const ffmpegResult = await ffmpegService.processReelFromUrl(resolveInternalUrl(media.originalUrl), {
             text: overlayText,
             musicUrl: finalMusicUrl,