fix(ui): lower-case hint preview words to match evaluate

A hint's MoveRecord words are upper-cased on decode (for the move-history view),
whereas an EvalResult keeps the backend's lower case. Seeding the move preview
from the hint verbatim flipped the score caption to upper case and nudged its
height. Lower-case the words in previewFromHint so the caption reads the same
as the evaluate path it replaces.

ui/src/lib/placement.test.ts

@@ -107,7 +107,7 @@ describe('placementFromHint', () => {
 });
 
 describe('previewFromHint', () => {
-  it('reuses the hint move as a legal preview, carrying score, words and direction', () => {
+  it('reuses the hint move as a legal preview, lower-casing words to match evaluate', () => {
     const preview = previewFromHint({
       player: 0,
       action: 'play',
@@ -120,7 +120,7 @@ describe('previewFromHint', () => {
       score: 18,
       total: 42,
     });
-    expect(preview).toEqual({ legal: true, score: 18, words: ['CAT', 'AN'], dir: 'V' });
+    expect(preview).toEqual({ legal: true, score: 18, words: ['cat', 'an'], dir: 'V' });
   });
 });
 

ui/src/lib/placement.ts

@@ -59,10 +59,13 @@ export function placementFromHint(tiles: Tile[], rack: string[]): Placement {
  * previewFromHint turns a hint's move into a move preview. A hint is the engine's own
  * top-ranked, fully scored legal play, so its move already carries the score, words and
  * direction an evaluate would compute for the same placement; reusing it lets the client
- * skip a redundant evaluate round-trip after auto-placing the hint.
+ * skip a redundant evaluate round-trip after auto-placing the hint. The words are
+ * lower-cased to match the evaluate result the caption renders: a hint's MoveRecord words
+ * are upper-cased on decode (for the move-history view), whereas an EvalResult keeps the
+ * backend's lower case, so reusing them verbatim would otherwise change the caption's case.
  */
 export function previewFromHint(move: MoveRecord): EvalResult {
-  return { legal: true, score: move.score, words: move.words, dir: move.dir };
+  return { legal: true, score: move.score, words: move.words.map((w) => w.toLowerCase()), dir: move.dir };
 }
 
 function usedIndexes(p: Placement): Set<number> {