Add extra prompts, endless generation, random character default, and small fixes

- Add extra positive/negative prompt textareas to all 9 detail pages with session persistence
- Add Endless generation button to all detail pages (continuous preview generation until stopped)
- Default character selector to "Random Character" on all secondary detail pages
- Fix queue clear endpoint (remove spurious auth check)
- Refactor app.py into routes/ and services/ modules
- Update CLAUDE.md with new architecture documentation
- Various data file updates and cleanup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

templates/partials/strengths_gallery.html

@@ -223,8 +223,8 @@
     col.className = 'col-6 col-sm-4 col-md-3 col-lg-2';
     col.innerHTML = `
       <div class="card h-100 sg-thumb" data-sg-strength="${strengthValue}">
-        <img src="${imageUrl}" class="card-img-top" style="object-fit:cover;height:160px;cursor:zoom-in;"
-             loading="lazy" onclick="window.open(this.src,'_blank')">
+        <img src="${imageUrl}" class="card-img-top sg-gallery-img" style="object-fit:cover;height:160px;cursor:zoom-in;"
+             loading="lazy" data-src="${imageUrl}">
         <div class="card-footer py-1 px-1">
           <div class="text-center mb-1"><span class="badge bg-secondary">${strengthValue}</span></div>
           <div class="d-flex gap-1">
@@ -236,6 +236,15 @@
         </div>
       </div>`;
     grid.appendChild(col);
+
+    // Add click handler for gallery navigation
+    const img = col.querySelector('.sg-gallery-img');
+    img.addEventListener('click', () => {
+      const allImages = Array.from(document.querySelectorAll('#sg-grid .sg-gallery-img')).map(i => i.dataset.src);
+      const index = allImages.indexOf(imageUrl);
+      openGallery(allImages, index);
+    });
+
     sgUpdateBadge();
     sgHighlightBounds();
   }