Highlight translation differences, first-draft snapshot, verse notes, paste check

- Compare translations can highlight the words that differ from the first
  translation (toggle remembered).
- A copy of your notes is kept the first time commentary is shown; "First draft,
  before commentary" under More shows what changed since. Saving it doesn't
  count as editing the chunk.
- Notes on single verses: a pencil next to each verse in Study, and a note line
  under each verse in Compare. They merge per verse across devices.
- Pasting 15+ words into a note asks "Is this from AI?"; "I wrote it" counts the
  words as yours again.

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

src/utils/mergeStudies.js

@@ -37,6 +37,10 @@ export function mergeChunk(mine, theirs) {
   LIST_FIELDS.forEach((f) => { out[f] = union(newer[f], older[f]); });
   // Pastes follow their text: keep the union per field so merged notes still show what was pasted.
   out.aiPastes = Object.fromEntries(['observation', 'interpretation', 'application'].map((f) => [f, union(newer.aiPastes?.[f], older.aiPastes?.[f])]));
+  // Verse notes are kept per verse (the newer wording wins, an older different one is appended); the earliest first draft is kept.
+  const noteKeys = new Set([...Object.keys(newer.verseNotes ?? {}), ...Object.keys(older.verseNotes ?? {})]);
+  out.verseNotes = Object.fromEntries([...noteKeys].map((k) => [k, mergeText(newer.verseNotes?.[k], older.verseNotes?.[k])]));
+  out.firstDraft = [newer.firstDraft, older.firstDraft].filter(Boolean).sort((a, b) => a.at - b.at)[0];
   out.followUps = mergeById(newer.followUps, older.followUps);
   out.recalls = union(newer.recalls, older.recalls);
   out.editedAt = Math.max(mine.editedAt ?? 0, theirs.editedAt ?? 0) || undefined;