fix: normalize empty HF token to None to fix auto-router error in InferenceClient

feat(app): enhance comic generation with improved error handling and user guidance

feat(comic): switch to FLUX API and generate validated 4-scene storyboards

Update file permissions and refactor app logic for comic generation. Improved error handling in inference function and enhanced logging for model loading. Cleaned up code formatting and removed dotenv dependency from config.

Add initial project structure for AI Comic Generation