Fix: Improve RunningHub API response handling and error diagnostics

[ErbolTakhirov]

Problem

Users with RunningHub Max membership were experiencing failures in v0.1.15 when using cloud workflows (both video generation and illustration generation). All workflows failed with:
"No valid JSON found: line 1 column 1 (char 0)"

While the membership and API key worked correctly on the RunningHub website, the integration in Pixelle-Video was broken, leaving 8GB VRAM GPU users with no viable cloud option.

Root Cause

The error occurred when ComfyKit received empty or invalid responses from the RunningHub API, but the code lacked:

• Proper validation that response objects weren't None
• Detailed error logging to diagnose response issues
• Clear error messages showing what went wrong and why

Solution

✅ Added comprehensive response validation and error handling across all workflow services:

• media.py: Image and video generation workflows
• tts_service.py: Text-to-speech workflows
• image_analysis.py: Image analysis workflows
• video_analysis.py: Video analysis workflows
• service.py: RunningHub API key configuration validation

Changes

1. Validate all ComfyKit responses are non-None before use
2. Log complete response object contents when errors occur
3. Show workflow parameters and inputs for reproduction
4. Validate RunningHub API key configuration during initialization
5. Provide clear error messages for debugging

Benefits

• Users now get detailed logs showing exactly what failed
• Easier to diagnose RunningHub connectivity issues
• Better error context for bug reports
• Clearer validation of configuration requirements

Testing

• All RunningHub workflows (video, image, TTS) now have proper error handling
• Error messages clearly indicate empty responses vs authentication failures
• Configuration validation prevents silent failures

[CLAassistant]

All committers have signed the CLA.