[Enhancement] Add custom output filename input before download

[magic-peach]

Overview

Allow users to specify the output filename before downloading. Currently the download uses a generic name like 'output.mp4'.

Implementation

In DownloadResult.tsx, add a text input for the filename:

<input 
  type="text" 
  value={filename}
  onChange={(e) => setFilename(e.target.value)}
  placeholder="my-video"
/>
<span>.mp4</span>

Use this as the download attribute on the anchor tag:

<a href={result.blobUrl} download={`${filename}.mp4`}>

Acceptance Criteria

• Filename input shown in DownloadResult
• Default value pre-populated from original filename (without extension)
• Downloaded file uses specified name
• Sanitizes invalid filename characters

[Swetanegi05]

Hi @magic-peach , please assign this to me

[Samiksha22911]

@magic-peach I'd like to work on this issue. Could you please assign it to me?

[magic-peach]

@Samiksha22911 @Swetanegi05 please star the repo