Optimize video grouping algorithm with dynamic sizing

[coderabbitai]

Background

Current implementation uses a fixed group size for media files, which may not be optimal for Telegram API limits.

Objectives

• Implement dynamic group sizing based on file sizes
• Optimize number of groups while staying within Telegram API limits
• Reduce the number of API requests needed for large carousels
• Avoid hitting API size limits

References

• PR feat:add Instagram story/carousel support with gallery-dl fallback  #37 discussion: feat:add Instagram story/carousel support with gallery-dl fallback  #37

/cc @yurnov