docs(user): update dashboard and bookshelf instructions for sidebar UI

Dashboard:
- Customize Dashboard is opened from the icon button at the right end
  of the Library bar (next to Refresh), and requires a specific library
  selected rather than 'All Libraries'
- Library switching uses the Library dropdown in the bar below the top
  bar (includes 'All Libraries' with counts)
- Collection sections are shown/hidden from the Customize Dashboard
  toggles — the per-collection 'Show on Dashboard' setting is gone
- Mention the hover chevrons for scrolling carousels

Bookshelf:
- Saved filters: document the new toolbar buttons — Filters (opens the
  filter drawer with Apply Filters, Esc, and overlay-click close), Save,
  Load (Saved Filters dropdown with trash-icon delete), and Clear —
  replacing the emoji-labelled Save Filter / Saved Filters buttons
- Tag filtering: filters now live behind the Filters drawer on the All
  Books page

docs/user/searching-and-filtering.md

@@ -13,10 +13,11 @@ Tags are keywords or categories assigned to books, such as:
 
 ### Filtering by Tags
 
-1. Navigate to the **Bookshelf** page
-2. Use the **Tags** filter input
-3. Start typing to see autocomplete suggestions
-4. Select a tag or press Enter to filter
+1. Navigate to the **All Books** page
+2. Click **Filters** in the toolbar to open the filter drawer
+3. Use the **Tags** filter input
+4. Start typing to see autocomplete suggestions
+5. Select a tag or press Enter, then click **Apply Filters**
 
 **Example:** Typing "Sci" will suggest "Science Fiction"