v0.4.4 — text annotation fixes

Fixed

• A text annotation was added twice for a single text box (user report). Chrome fires blur on the textarea while it is being removed from the DOM, so pressing Enter ran the commit once for the key and once for that blur — the text was drawn on top of itself and Undo had to be pressed twice to remove it. The commit is now gated by a synchronously cleared anchor, so whichever trigger fires first commits and the rest are no-ops.
• Every text box after the first one opened unfocused and swallowed the typing: the autofocus attribute is processed only once per document. The editor now focuses the box explicitly when it opens.
• Escape now really discards the draft and closes the box. It used to leave the box behind, and a leftover box blocks onPointerDown — which made every drawing tool go dead until the editor was reopened.

Added

• scripts/probe-text-dup.mjs — focused Playwright repro for the text-box commit path; the same assertions run inside the main E2E suite (scripts/e2e.mjs).