fix: fix caret error on incorrect final word (@Positiveoo1)

[Positiveoo1]

Fixes #8180

Summary

• Render incorrect committed words before word change UI updates
• Prevent caret positioning from throwing when target word has no rendered letters yet

Testing

• Custom text: a a
• Typed a, space, f, space
• Confirmed console no longer throws Caret getTargetPositionAndWidth: no letters found in word

[Copilot]

Pull request overview

Fixes a frontend caret crash that can occur when moving past an incorrectly-typed final word by (a) ensuring the word’s <letter> DOM is updated on incorrect word transitions and (b) making caret positioning more defensive when expected <letter> nodes are missing.

Changes:

• Update beforeTestWordChange to call updateWordLetters when correct === false.
• Adjust caret target resolution to fall back when the requested letter index isn’t present (instead of throwing).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
frontend/src/ts/test/test-ui.ts	Forces word-letter DOM refresh when leaving an incorrect word to keep caret/word rendering consistent.
frontend/src/ts/elements/caret.ts	Avoids throwing when no target <letter> exists; adds fallback positioning logic.

[Miodec]

I think i would change this to something like

const letters = options.word?.qsa("letter");

if (letters.length === 0) {
  throw new Error(
    "Caret getTargetPositionAndWidth: no letters found in word",
  );
}

const letter = letters[options.letterIndex] ?? letters[letters.length - 1];

if (!letter) {
  throw new Error(
    `Caret getTargetPositionAndWidth: letter not found for index ${options.letterIndex}`,
  );
}

if (caretDebug) {

[Miodec]

And revert this. This code will be changed soon anyway.