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/components/study/FirstDraft.jsx

@@ -0,0 +1,36 @@
+// "What changed since my first draft": your Observe / Interpret / Apply notes now, with the words added or
+// reworded since the copy kept when you first opened commentary. It shows whether commentary changed your thinking.
+import { diffVerses } from '../../utils/textDiff.js';
+import { markRanges } from '../../utils/compareTranslations.js';
+
+const FIELDS = [['observation', 'Observe'], ['interpretation', 'Interpret'], ['application', 'Apply']];
+const count = (s) => (s ?? '').trim().split(/\s+/).filter(Boolean).length;
+
+export default function FirstDraft({ chunk }) {
+  const draft = chunk.firstDraft;
+  if (!draft) return null;
+  const rows = FIELDS.map(([f, label]) => {
+    const then = draft[f] ?? '';
+    const now = chunk[f] ?? '';
+    return { f, label, then, now, same: then.trim() === now.trim(), parts: markRanges(now, diffVerses(then, now).b) };
+  }).filter((r) => r.then.trim() || r.now.trim());
+  const changed = rows.filter((r) => !r.same).length;
+  return (
+    <details className="rounded-xl border border-[var(--r-line)] p-3 text-xs text-[var(--r-sub)]">
+      <summary className="cursor-pointer">First draft, before commentary <span className="opacity-70">· {new Date(draft.at).toLocaleDateString()} · {changed === 0 ? 'nothing changed since' : `${changed} of ${rows.length} notes changed since`}</span></summary>
+      <div className="mt-3 space-y-3">
+        {rows.length === 0 && <p>You opened commentary before writing anything.</p>}
+        {rows.map((r) => (
+          <div key={r.f}>
+            <p className="font-medium text-[var(--r-text)]">{r.label} <span className="font-normal text-[var(--r-sub)]">· {count(r.then)} words then, {count(r.now)} now</span></p>
+            {r.same
+              ? <p className="mt-0.5">Unchanged.</p>
+              : <p className="mt-0.5 whitespace-pre-line font-serif text-[13px] leading-relaxed text-[var(--r-text)]">{r.parts.map((p, i) => (p.mark ? <mark key={i} className="rounded bg-[var(--r-hl)] px-0.5 text-inherit">{p.text}</mark> : <span key={i}>{p.text}</span>))}</p>}
+            {!r.same && r.then.trim() && <details className="mt-1"><summary className="cursor-pointer">Show the first draft</summary><p className="mt-1 whitespace-pre-line font-serif text-[13px] leading-relaxed">{r.then}</p></details>}
+          </div>
+        ))}
+        <p className="opacity-70">Highlighted words are new or reworded since the draft.</p>
+      </div>
+    </details>
+  );
+}