Notebook: write your own note (alongside captured lines)

The field notebook gets a handwriting input to add a custom note manually;
it posts to the same notebook store and can be torn to the board like a
captured one.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/inventory.tsx

@@ -112,6 +112,7 @@ export function Inventory({ onClose, session, onTearToBoard }: { onClose?: () =>
 // onto the board as a note (when a board tear handler is available).
 function NotebookTool({ playthroughId, onTear }: { playthroughId?: string; onTear?: (text: string) => void }) {
   const [pages, setPages] = useState<{ id: string; text: string }[]>([])
+  const [draft, setDraft] = useState('')
   useEffect(() => {
     if (!playthroughId) return
     fetch(`/api/playthroughs/${playthroughId}/notebook`).then(r => r.ok ? r.json() : []).then(setPages).catch(() => {})
@@ -121,10 +122,20 @@ function NotebookTool({ playthroughId, onTear }: { playthroughId?: string; onTea
     setPages(list => list.filter(page => page.id !== id))
   }
   const tear = (page: { id: string; text: string }) => { onTear?.(page.text); void remove(page.id) }
+  const add = async () => {
+    const text = draft.trim()
+    if (!text || !playthroughId) return
+    const res = await fetch(`/api/playthroughs/${playthroughId}/notebook`, { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ text }) })
+    if (res.ok) { const page = await res.json(); setPages(list => [...list, { id: page.id, text: page.text }]); setDraft('') }
+  }
   return <div className="notebook">
     <div className="notebook-page">
       <div className="notebook-head">FIELD NOTEBOOK</div>
-      {!pages.length && <p className="notebook-empty">Nothing noted yet. During a conversation, use “✎ Note this” to jot down what someone says.</p>}
+      {playthroughId && <div className="notebook-add">
+        <textarea value={draft} onChange={event => setDraft(event.target.value)} placeholder="Write your own note…" spellCheck={false} rows={2} />
+        <button disabled={!draft.trim()} onClick={add}>+ Add</button>
+      </div>}
+      {!pages.length && <p className="notebook-empty">Nothing noted yet. Write one above, or during a conversation use “✎ Note this”.</p>}
       {pages.map(page => <div key={page.id} className="notebook-note">
         <p>{page.text}</p>
         <div className="notebook-note-actions">