feat(file-upload): implement selecting and uploading file via button on the editor toolbar

[purnimagarg1]

Linear ticket:
https://linear.app/acryl-data/issue/CH-831/implement-ui-for-prompting-user-to-select-file-from-their-system

Description:

This adds a new button in rich text editor toolbar to upload file and handles file upload using the existing FileDragDropExtension

Screenshot:

Video:

Screen.Recording.2025-10-17.at.4.21.47.PM.mov

[alwaysmeticulous]

🔴 Meticulous spotted visual differences in 12 of 993 screens tested: view and approve differences detected.

Meticulous evaluated ~9 hours of user flows against your PR.

_{Last updated for commit a64c12a. This comment will update as new commits are pushed.}

[codecov]

Bundle Report

Changes will increase total bundle size by 5.6kB (0.02%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
datahub-react-web-esm	28.6MB	5.6kB (0.02%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: datahub-react-web-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
assets/index-*.js	5.6kB	18.94MB	0.03%

Files in assets/index-*.js:

• ./src/alchemy-components/components/Editor/toolbar/FileUploadButton.tsx → Total Size: 2.91kB

• ./src/alchemy-components/components/Editor/toolbar/Toolbar.tsx → Total Size: 3.74kB

• ./src/alchemy-components/components/Editor/extensions/fileDragDrop/FileDragDropExtension.tsx → Total Size: 7.25kB

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!