Open same-origin links in the same tab

[virgile-dev]

Problem to solve

In order to move between documents and sections of an app built on BlockNote, users need internal links to behave like in-app navigation. Today, clicking a link in the editor opens it in a new tab, even when it points to the same app. Linking to another block in the same document or to another document opens a new tab every time. Users lose their place and end up with many tabs.

Out of scope

• Telling a document URL apart from other same-origin URLs (attachments, API routes) depends on the app's routing. BlockNote should expose a hook or option for this (e.g. a resolveLink / onLinkClick callback) rather than guess.
• In-app navigation (e.g. Next.js router) is done by the integrating app through that callback.

Implementation

TBD. Possible lead: add a base URL option and a link click handler to the editor, falling back to target="_blank" when the handler does not take the link over.

[virgile-dev]

Since we stumbled on this problem when we integrated link to blocks.
It's worth linking this discussion as well : #3063