Support progressive selection with Cmd/Ctrl + A (block → document) #2402

It would be great if BlockNote supported progressive selection when using Cmd / Ctrl + A.

Currently, pressing Cmd / Ctrl + A selects the entire document. This makes it harder to quickly operate on the content of a single block.

Expected Behavior

• First press of Cmd / Ctrl + A
  • Selects the content of the current block only
• Second press of Cmd / Ctrl + A
  • Selects the entire document

This behavior is expected to be applied when the cursor is inside a block (built-in or custom).

Current Behavior

• A single press of Cmd / Ctrl + A always selects the entire document
• There is no native way to quickly select only the current block’s content using the keyboard

This would significantly improve usability for users working with block-based content and performing frequent keyboard-driven edits.