book(D2 polish): manifest dirty tracking + feed-card preview

Two pieces that close out Phase D2:

Dirty tracking
- isBookManifestDirty() compares the current bookManifestPayload
  serial to state.book.lastPublishedManifestSerial; a missing
  snapshot but any existing ref counts as dirty so the sidebar
  prompts the first publish.
- markBookManifestClean() snapshots the serial on success; called
  from both the public and private manifest publish paths in
  publishCurrentTemplateToNostr.
- syncBookSidebarSummary renders a one-line hint —
  "⚠ Manifest has unsaved changes" or "✓ Manifest is in sync" —
  so authors see when sidecar publishes have outpaced the manifest
  publish.

Feed-card preview
- buildFeedCard now has a `book` branch: a chapbook-shaped card
  (cream-to-amber gradient, Georgia serif title, page + chapter
  counts) so book manifests don't fall through to a blank "Preview
  unavailable" tile in the community browser.
- MODE_LABELS gets 'book': 'Book' so the type chip + fallback label
  read correctly.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/index.html

@@ -10531,6 +10531,36 @@
       return summary;
     }
 
+    // Manifest dirty tracking. After a successful manifest publish
+    // we snapshot the serialised payload onto state.book.lastPublishedManifestSerial;
+    // isBookManifestDirty() compares the current serialisation to
+    // that snapshot. Used by the sidebar hint so the user knows when
+    // the manifest needs another publish.
+    function isBookManifestDirty() {
+      const book = state.book;
+      if (!book) return false;
+      const snapshot = book.lastPublishedManifestSerial;
+      if (!snapshot) {
+        // No snapshot but we have refs → counted as dirty so the
+        // sidebar prods the user to publish for the first time.
+        const hasAnyRef = !!book.cover?.ref
+          || (book.masters || []).some(m => m.ref)
+          || (book.pages || []).some(p => p.ref || p.textRef);
+        return hasAnyRef;
+      }
+      try {
+        const current = JSON.stringify(bookManifestPayload());
+        return current !== snapshot;
+      } catch {
+        return false;
+      }
+    }
+    function markBookManifestClean() {
+      const book = state.book;
+      if (!book) return;
+      try { book.lastPublishedManifestSerial = JSON.stringify(bookManifestPayload()); } catch {}
+    }
+
     // Build the casewrap-book manifest payload. Lean — references
     // sibling page / master / cover / chapter events via {kind, pubkey,
     // dTag} coords instead of inlining their layers. Phase D1 hands
@@ -11157,11 +11187,24 @@
         ? `derived from ${pageCount} page${pageCount === 1 ? '' : 's'}`
         : 'manual';
       const fmt = (n) => Number(n).toFixed(n % 1 === 0 ? 0 : 3);
+      // Manifest dirty hint — sidecars publish independently, so the
+      // manifest can be "out of sync" with the per-page events. Tell
+      // the user explicitly so they don't think Publish-page was the
+      // last step.
+      let dirtyHint = '';
+      try {
+        if (isBookManifestDirty()) {
+          dirtyHint = '<br><span style="color:#92400e">⚠ Manifest has unsaved changes — Publish to update the casewrap-book event.</span>';
+        } else if (state.book.lastPublishedManifestSerial) {
+          dirtyHint = '<br><span style="color:#15803d">✓ Manifest is in sync with the published casewrap-book event.</span>';
+        }
+      } catch {}
       el.innerHTML = ''
         + `<b>${s.bookSize || 'Custom'}</b> · ${fmt(s.trimW)} × ${fmt(s.trimH)} in`
         + `<br>Bleed ${fmt(s.bleed)} in · Paper ${fmt(s.paperThickness)} in/page`
         + `<br>Spine ${fmt(spineW)} in <span class="hint">(${spineNote})</span>`
-        + `<br>${pageCount} page${pageCount === 1 ? '' : 's'} · ${(state.book.masters || []).length} master${(state.book.masters || []).length === 1 ? '' : 's'}`;
+        + `<br>${pageCount} page${pageCount === 1 ? '' : 's'} · ${(state.book.masters || []).length} master${(state.book.masters || []).length === 1 ? '' : 's'}`
+        + dirtyHint;
       syncBookVisibilityChip();
     }
     // Sync the Public/Private chip in the book sidebar from
@@ -21648,6 +21691,9 @@
         const signed = await publishEncryptedDesign(payload);
         const label = isEditing() ? `Updated "${state.meta.title}" (private)` : `Private "${state.meta.title}"`;
         await finalizePublishedTemplateEvent(signed, { label });
+        if (state.templateMode === 'book' && typeof markBookManifestClean === 'function') {
+          try { markBookManifestClean(); } catch {}
+        }
         if (isEditing()) exitEditMode();
         return signed;
       }
@@ -21677,6 +21723,12 @@
       const signed = await publishCommunityEvent(evt);
       const label = isEditing() ? `Updated "${state.meta.title}"` : `Template "${state.meta.title}"`;
       await finalizePublishedTemplateEvent(signed, { label });
+      // Book manifest: snapshot the published serialisation so the
+      // sidebar's dirty hint flips to "Saved" until the user makes
+      // another manifest-affecting change.
+      if (state.templateMode === 'book' && typeof markBookManifestClean === 'function') {
+        try { markBookManifestClean(); } catch {}
+      }
       if (isEditing()) exitEditMode();
       return signed;
     }
@@ -29098,6 +29150,25 @@
           else if (row.mode === 'customart' || row.mode === 'slide') renderCustomArtPreviewDOM(previewWrap, payload, { compact: true });
           else if (row.mode === 'deck') renderDeckPreviewDOM(previewWrap, payload, { compact: true });
           else if (row.mode === 'pixelart') renderPixelArtPreviewDOM(previewWrap, payload, { compact: true });
+          else if (row.mode === 'book') {
+            // Book manifests don't ship layer data — render a
+            // chapbook-shaped card with title + entry counts so the
+            // feed has something to display instead of "Preview
+            // unavailable".
+            const spec = payload.book?.spec || {};
+            const pages = payload.book?.pages || [];
+            const designed = pages.filter(p => p.type === 'design').length;
+            const reflow = pages.filter(p => p.type === 'reflow').length;
+            const trimLabel = spec.bookSize || `${spec.trimW || 6} × ${spec.trimH || 9} in`;
+            previewWrap.style.cssText = 'width:100%;height:100%;display:flex;align-items:center;justify-content:center;padding:14px;box-sizing:border-box;background:linear-gradient(135deg,#fef3c7 0%,#fde68a 50%,#f59e0b 100%)';
+            previewWrap.innerHTML = `
+              <div style="display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;font-family:Georgia,serif;color:#1f2937;padding:18px 14px;background:rgba(255,255,255,.85);border:1px solid #d97706;border-radius:4px;max-width:90%">
+                <div style="font-size:1rem;font-weight:700;line-height:1.2;margin-bottom:6px;word-break:break-word">${escapeHtml(payload.meta?.title || 'Untitled book')}</div>
+                <div style="font-size:.72rem;color:#92400e">${escapeHtml(trimLabel)}</div>
+                <div style="font-size:.7rem;color:#92400e;margin-top:8px">${designed} page${designed === 1 ? '' : 's'}${reflow ? ` · ${reflow} chapter${reflow === 1 ? '' : 's'}` : ''}</div>
+              </div>
+            `;
+          }
           else renderTemplatePreviewDOM(previewWrap, payload, { compact: true });
         } catch {}
       }
@@ -29865,7 +29936,7 @@
       return btn;
     }
 
-    const MODE_LABELS = { cover: 'Case cover', disc: 'Disc sheet', jewel: 'CD jewel inserts', 'disc-design': 'Disc design', customart: 'Custom art', slide: 'Slide', deck: 'Slide deck', pixelart: 'Pixel art' };
+    const MODE_LABELS = { cover: 'Case cover', disc: 'Disc sheet', jewel: 'CD jewel inserts', 'disc-design': 'Disc design', customart: 'Custom art', slide: 'Slide', deck: 'Slide deck', pixelart: 'Pixel art', book: 'Book' };
 
     function buildDiscSheetThumb(thumb, payload, compact = false) {
       const slots = payload?.discTemplate?.discs || payload?.discs || {};