Close latent Matins Gospel-homily dedup gap

When a Gospel+homily pair is folded into one pool entry, the homily's
own text was never registered in seenReadingText -- only the Gospel
pericope's text was. Not live for any date today, but the same
structural mistake already fixed once for two ids pooling the same
Gregory the Great excerpt: a later pooled id whose solo lesson happens
to share a homily's exact text would render as a visible duplicate.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T6rG4RTNqLFYcyjbCGkPFs

src/hours/matins.ts

@@ -966,7 +966,11 @@ function buildReadingPool(day: LiturgicalDay, temporalId: string, date: string,
         const next = readings[i + 1];
         const homily = next && !next.isGospel && next.nocturn === reading.nocturn ? next : undefined;
         bucket.push(gospelReadingPart(reading, homily, id, commonPoolIndex++, day));
-        if (homily) i++;
+        if (homily) {
+          i++;
+          const homilyKey = homily.text.la ?? homily.text.en ?? '';
+          if (homilyKey) seenReadingText.add(homilyKey);
+        }
       } else {
         bucket.push(nocturnReadingPart(reading, id, commonPoolIndex++, day));
       }