Add user-provided on-video text variations for Trial Reels#2909

Please add a feature to create user-provided on-video text variations for Trial Reels while scheduling.

Current issue:
When creators test multiple Trial Reels, they often need to add different text on the video itself, such as first-frame hooks, title text, CTA lines, local-language text, or question-based hooks.

Right now, these text variations have to be added manually in another video editing app before uploading to Publer.

Suggested solution:
Allow users to upload one video and provide their own text variations. Publer should apply each user-provided text line as an on-video overlay and create separate rendered video versions.

Example:
Upload one Reel and add 5 user-provided text variations:

1. Text variation 1
2. Text variation 2
3. Text variation 3
4. Text variation 4
5. Text variation 5

Publer then creates 5 separate video versions using the same base video but different on-video text overlays.

Useful options:

• User provides the text manually
• Add text only on the first 2 to 3 seconds
• Choose text position, size, font, and background box
• Duplicate the same video with different text overlays
• Apply one text variation to each scheduled Trial Reel
• Save each variation as a separate rendered video version

This would help users test which on-video hook performs better and avoid repeatedly uploading the exact same video file with no creative variation.