Fix: Improve X media extraction and manual cookie fallback

[SiIverAsh]

Summary

This PR improves X media extraction and fallback behavior.

Changes

• add a manual cookie setting that can be used when downloads fail
• pass the manual cookie into X native requests and yt-dlp fallback
• skip cookies-from-browser when an explicit Cookie: header is already provided
• improve X media extraction for nested, quoted, and retweeted media structures
• improve fallback error reporting so native and yt-dlp failures are both visible
• support original-size X photo URLs
• treat multi-item X posts as multi-file media consistently

Why

Some X posts could fail with No media found in tweet even when media existed.

There were several failure modes behind that:

• public endpoints returning tombstone or unavailable results
• media being nested inside quoted or retweeted tweet structures
• HLS-only video variants
• yt-dlp fallback being blocked by cookie, browser-cookie, or proxy issues
• photo posts needing better handling

This PR makes the extraction path more robust and adds a manual cookie fallback when automatic cookie handling is not enough.

Validation

Tested locally with:

• a X video URL that previously failed with No media found in tweet
• a X video URL that already worked
• X image and mixed-media parsing behavior in the updated extraction path

[tonhowtf]

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