Feature Request: Optional File Picker for Source and Output Paths

Hi!
I'd like to propose an optional file-picker mode for MarkItDown.
Many users especially on Windows are not comfortable working with file paths in the terminal. especially if files are located on different drives.
Currently, users must specify paths explicitly:
markitdown path-to-file.pdf -o document.md

A possible enhancement would be to provide an optional flag that opens the system file picker to select the input file (and optionally the output location).

Examples:

# Select source file via file picker
markitdown --pick-file -o document.md

# Select both source and destination
markitdown --pick-file --pick-output

Alternatively, a single --gui flag could open dialogs for any missing paths.

This would remain completely optional and would not affect existing CLI workflows, scripts, automation, CI/CD usage, or headless environments.
I believe this could improve accessibility for less technical users (especially for vibe coders) while preserving the current command-line experience.
If this sounds useful, I'd be happy to work on an implementation and submit a pull request.

thanks for reading and have a great day!

Start by reviewing the CLI argument handling for the existing input path and -o output path, then decide whether the proposed --pick-file/--pick-output or --gui behavior fits supported platforms. Verify that normal path-based use, scripts, CI/CD, and headless environments remain unaffected; done means optional source and destination selection works without changing existing workflows.