docs(storage): add comprehensive JSDoc documentation to GetSignedUrlConfig interface properties

[thiyaguk09]

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request reorganizes the properties of the GetSignedUrlConfig interface in handwritten/storage/src/file.ts and adds comprehensive JSDoc documentation to each field to improve code readability and developer experience. No review comments were provided, and there is no additional feedback.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.