fix: preserve cursor position when editing blog content

[santoslgl01-web]

Summary

• initialize the Tiptap editor with the fetched post HTML
• avoid resetting the document when the current editor HTML already matches the incoming content
• sync external content changes back into the editor without emitting another update, which preserves the user's caret position while typing

Testing

• npm run lint
• npm run build

Fixes #31

[vercel]

@santoslgl01-web is attempting to deploy a commit to the safvantsy's projects Team on Vercel.

A member of the Team first needs to authorize it.

[santoslgl01-web]

Thanks for the PR checks. The code fix is complete; the only failing item is Vercel deployment authorization on the maintainer team side (Authorization required to deploy.), which I cannot approve as an external contributor. Please let me know if you would like any code changes beyond that.