restoreCursor

Restores the core-owned state saved by saveCursor (DECRC, ESC 8).

The restored state includes:

• cursor column

• cursor row

• pen attributes

• pending-wrap state

• origin mode (DECOM)

If no cursor has been saved, the core homes the cursor to absolute (0, 0), clears origin mode, and resets the pen to its default, matching the current xterm-style fallback implemented by the core.

Charset designation and shift state remain outside this contract because they belong to the parser layer, not to :terminal-core.