feat(ui) Add new file upload to S3 extension in the UI

[chriscollins3456]

This PR builds a new extension that allows us to drag and drop files into our rich text Editor component and upload them to S3, completing the desired flow of requesting a presigned URL, uploading to S3, then rendering a classic markdown link/image with a reference to our own file service REST API (what this PR is built on top of).

Right now this is only enabled on the new summary tab, but we have another PR coming out where we can support this for all entity documentation and extend support elsewhere as well.

Screen.Recording.2025-10-14.at.12.49.30.PM.mov

[alwaysmeticulous]

✅ Meticulous spotted 0 visual differences across 950 screens tested: view results.

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

_{Expected differences? Click here. Last updated for commit 9367e7d. This comment will update as new commits are pushed.}

[codecov]

Bundle Report

Changes will increase total bundle size by 8.25kB (0.03%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
datahub-react-web-esm	28.6MB	8.25kB (0.03%) ⬆️

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	8.25kB	18.94MB	0.04%

Files in assets/index-*.js:

• ./src/alchemy-components/components/Editor/extensions/fileDragDrop/fileUtils.ts → Total Size: 3.78kB

• ./src/alchemy-components/components/Editor/extensions/fileDragDrop/FileNodeView.tsx → Total Size: 1.66kB

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

• ./src/alchemy-components/components/Editor/extensions/markdownToHtml.tsx → Total Size: 592 bytes

• ./src/alchemy-components/components/Editor/Editor.tsx → Total Size: 2.72kB

• ./src/app/entityV2/summary/documentation/EditDescriptionModal.tsx → Total Size: 1.61kB

• ./src/alchemy-components/components/Editor/extensions/htmlToMarkdown.tsx → Total Size: 4.57kB

• ./src/app/shared/hooks/useFileUpload.ts → Total Size: 1.0kB

• ./src/app/shared/Loading.tsx → Total Size: 852 bytes

[codecov]

Codecov Report

❌ Patch coverage is 98.39572% with 3 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...components/Editor/extensions/fileDragDrop/index.ts	0.00%	3 Missing ⚠️

📢 Thoughts on this report? Let us know!

[v-tarasevich-blitz-brain]

Somewhere we have to add checking of our feature flag to enable/disable uploading

[v-tarasevich-blitz-brain]

can we generate the pattern from EXTENSION_TO_FILE_TYPE to keep them in sync?