fix: three post-review corrections

- Filter source tags from gallery overlay refresh in view-modal.js and bulk-select.js
- Fix split(':', 1) bug causing series name to render as "undefined"
- Offset reader quick-nav above floating page indicator to prevent overlap

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

app/static/js/bulk-select.js

@@ -508,8 +508,8 @@
 
       if (!data.ok) return;
 
-      // Filter out archive tags (they're not shown)
-      const visibleTags = (data.tags || []).filter(t => t.kind !== 'archive');
+      // Filter out archive and source tags (they're not shown in overlays)
+      const visibleTags = (data.tags || []).filter(t => t.kind !== 'archive' && t.kind !== 'source');
 
       // Find or create tag overlay
       let overlay = item.querySelector('.tag-overlay');