Let a text field select from right to left with the mouse (#236)

Dragging from right to left in a canvas text field only moved the
cursor. The hidden input behind the field got every selection sorted
and without a direction. Its selectionchange echo then handed back the
sorted range, and the anchor jumped to the mouse on the first move.

- KeyboardBridge sets the selection with 'backward' when the focus
  lies before the anchor, and reads selectionDirection when the input
  reports a change.
- TextField passes anchor and focus through unchanged. Its own
  sorting is gone.
- Shift+Left runs through the same path. The cursor should now sit at
  the moving end there too. This is not tested on its own.

Tests:
- ./check.sh: 167 files, 2435 tests, CHECK EXIT 0
- e2e 2: ALL PASSED, 25 checks. New check 2d-ii drags right to left
  in the name field and reads start 0, end 13, direction backward.
- Counter-check without the direction: 2d-ii fails with end 2, the
  reported symptom.
- e2e check total in README goes to 1401 (computed, not run in full).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tools/e2e/02-inspector.mjs

@@ -105,6 +105,24 @@ export async function inspector(t) {
     JSON.stringify((await object('o2')).name),
   );
 
+  // 2d-ii. A drag from right to left selects the whole name (#236). The hidden input reported its
+  //     range ordered, and its selectionchange echo made the caret the anchor after the first move.
+  await click(nameLabel.x + 160, nameLabel.y);
+  const nameField = await json('__gm.focusedRect()');
+  await press('Escape');
+  const midY = nameField.y + nameField.h / 2;
+  await drag(nameField.x + nameField.w - 4, midY, nameField.x + 3, midY);
+  const backward = await json(
+    '({ start: document.activeElement?.selectionStart, end: document.activeElement?.selectionEnd,' +
+      ' direction: document.activeElement?.selectionDirection })',
+  );
+  await press('Escape');
+  check(
+    'dragging from right to left selects the whole name',
+    backward.start === 0 && backward.end === 'Renamed crate'.length && backward.direction === 'backward',
+    JSON.stringify(backward),
+  );
+
   // 2e. Scrub the X field (right of the "X" label) by 100 px.
   const xLabel = await locate('X');
   await drag(xLabel.x + 160, xLabel.y, xLabel.x + 260, xLabel.y);