fix: support multi-file uploads in upload_file

[zerone0x]

Summary

• allow upload_file to accept multiple file paths via filePaths (keeps filePath for single uploads)
• pass arrays through to Puppeteer uploadFile / fileChooser accept
• document new argument in CLI tool definitions

Testing

• not run (no test suite for this change)

Fixes #1217

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[Lightning00Blade]

Please revert any changes unrelated to the description of the PR (like protocolTimeout).

[zerone0x]

updated upload_file to accept comma-separated values in filePath (e.g. --filePath 'a.txt,b.txt'), plus updated arg descriptions. pushed in 0e3862c.