Add advanced wishlist metadata, management UI, and product-page quick actions

[Copilot]

This PR extends wishlist items from a binary saved list into a metadata-rich workflow (notes, priority, category, target price, quantity) with power-user controls for filtering, grouping, and bulk operations. It also connects product browsing to wishlist metadata capture and high-priority signaling.

• Data model + wishlist state layer

  • Introduces an extended WishlistItem shape with backward-compatible normalization for legacy entries.
  • Adds WishlistContext methods for per-field updates (notes, priority, category, targetPrice, quantity), bulk actions, and helper APIs for filtering/sorting.
  • Persists wishlist and purchase history in localStorage and exposes analytics helpers (category usage, priority distribution, average days to purchase).

• Wishlist management surface

  • Adds Wishlist.tsx (new route) with:
    • priority/category filters
    • sort by date/priority/price
    • category grouping with color chips
    • empty states per current view
    • keyboard shortcuts (e, p, c) for edit/priority/category
    • bulk actions: move category, set priority, delete selection
  • Adds WishlistItemCard.tsx with:
    • expandable product details
    • debounced note autosave + blur save
    • inline priority/category/target price/quantity editing
    • quick actions: Buy Now, Add to Cart, Remove
    • priority badges/icons (🔴 high, 🟡 medium, ⚪ low)

• Products integration

  • Adds wishlist quick-add (defaults) and metadata modal flow (notes + priority).
  • Displays high-priority wishlist badge on product cards.
  • Replaces blocking alerts with inline feedback messaging for UX continuity.

• App wiring

  • Registers WishlistProvider, /wishlist route, and navigation entry.

// Context API now supports metadata-first item management
addToWishlist(productId, { notes, priority, category, targetPrice, quantity });
updateItemNotes(productId, notes);
updateItemPriority(productId, 'high');
updateItemCategory(productId, 'Seasonal');
sortByPriority(items);
getItemsByCategory('Seasonal');

Original prompt

Add advanced features to the wishlist: notes, priorities, categories, and quick actions to enhance the user experience.

Goal: Extend the wishlist functionality with power-user features that make product management more efficient.

Requirements:

1. Enhanced Data Model:

   interface WishlistItem {
     wishlistItemId: number;
     wishlistId: number;
     productId: number;
     addedAt: string;
     notes?: string;              // User notes about why they want this
     priority?: 'high' | 'medium' | 'low';  // Priority level
     category?: string;           // Custom category/collection
     targetPrice?: number;        // Desired price point
     quantity?: number;           // Desired quantity (default 1)
   }

2. Frontend Components:

   • Wishlist.tsx enhancements:

     • Add filter/sort by priority, category, date added
     • Group items by category
     • Inline note editing
     • Priority badges (color-coded)
     • Quick "add to cart" button with quantity selector
     • "Move to category" dropdown

   • New Component: WishlistItemCard.tsx:

     • Expandable card showing product details
     • Note textarea (auto-save on blur)
     • Priority selector dropdown
     • Category input/select
     • Target price input
     • Last price check indicator
     • Quick actions: "Buy Now", "Add to Cart", "Remove"

3. Products.tsx Integration:

   • When adding to wishlist, show modal to add notes/priority
   • Quick-add option (skip modal, use defaults)
   • Show wishlist icon badge if item has high priority

4. Context Updates (WishlistContext.tsx):

   • Add methods: updateItemNotes, updateItemPriority, updateItemCategory
   • Add filtering helpers: getItemsByPriority, getItemsByCategory
   • Add sorting helpers: sortByDateAdded, sortByPriority, sortByPrice
   • Maintain localStorage/API sync

5. Backend API Updates (if Variation 1 merged):

   • PATCH /api/wishlists/:userId/items/:productId - Update item metadata
   • GET /api/wishlists/:userId/items?priority=high - Filter by priority
   • GET /api/wishlists/:userId/categories - Get unique categories

6. UI/UX Features:

   • Category chips with color coding
   • Priority icons (🔴 high, 🟡 medium, ⚪ low)
   • Bulk actions: "Move to category", "Set priority", "Delete selected"
   • Empty state messages per filter/category
   • Keyboard shortcuts (e, p, c for edit, priority, category)

7. Analytics Tracking:

   • Track most used categories
   • Track average days until purchase
   • Track priority distribution

Technical Notes:

• Maintain backwards compatibility with simple wishlist items
• Use debouncing for auto-save note edits
• Add input validation for target price, quantity
• Implement optimistic UI updates
• Add loading states for async operations