AI Lyrics Translation fails with OpenRouter Custom OpenAI Compatible API

Duplicate Check

• I confirm I searched for existing reports and found no duplicates.

Describe the Bug

Hello,

I am testing the AI Lyrics Translation feature, but translated lyrics are not appearing.

AI Setup:

• AI Provider: Custom OpenAI Compatible
• Base URL: "https://openrouter.ai/api/v1"
• Model: "google/gemma-4-26b-a4b-it:free"
• Translation language: "en"

Testing:
I tested the same OpenRouter configuration using cURL, and the API works correctly. The model successfully returns translated text.

Example response:
"The English translation is: "Hello my love, how are you?""

Issue:
Inside SimpMusic:

• API key is accepted
• Use AI Lyric Translation is enabled
• Lyrics are available
• But AI-translated lyrics are not displayed

Actual behavior:
No translated lyrics appear.

Could you please check if Custom OpenAI Compatible endpoints like OpenRouter are fully supported by the AI Lyrics Translation beta feature?

Steps to Reproduce

1. Open Settings → AI
2. Select Custom OpenAI Compatible
3. Enter OpenRouter API key
4. Set Base URL and model ID
5. Enable Use AI Lyric Translation
6. Play a non-English song with lyrics

Expected Behavior

Lyrics should be translated into English.

App Version

v1.6.0

Android Version

Android 15

Device Model

Samsung A06

Custom ROM

• I am using a custom ROM

Custom ROM Name (if applicable)

No response

Screenshots (optional)

No response

Log / Error Details

No response

Start in Settings → AI and reproduce the AI Lyrics Translation flow with the listed OpenRouter-compatible configuration, comparing the app behavior with the successful cURL response. Done means translated lyrics appear for a non-English song when the feature is enabled; the issue provides no file or test names, so trace the Android translation path first.