Add category-grouped store picker on search page

Replaces dropdown filters with visual store picker organized by
category. Each category shows as a header with checkbox — clicking
it selects/deselects all stores in that category. Individual stores
are toggleable chips with checkmarks. Partial selection shows a
dash indicator on the category checkbox. Only passes specific
store IDs to search when not all stores are selected.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/src/routes/+page.svelte

@@ -1,34 +1,100 @@
 <script>
   import { goto } from '$app/navigation';
-  import { getCategories, getGroups } from '$lib/api';
+  import { getCategories, getStores } from '$lib/api';
   import { onMount } from 'svelte';
 
   let query = $state('');
   let categories = $state([]);
-  let groups = $state([]);
+  let stores = $state([]);
-  let selectedCategory = $state('');
+  let selectedStoreIds = $state(new Set());
-  let selectedGroup = $state('');
+  let allSelected = $state(true);
 
   onMount(async () => {
     try {
-      [categories, groups] = await Promise.all([getCategories(), getGroups()]);
+      [categories, stores] = await Promise.all([getCategories(), getStores()]);
+      // Start with all enabled stores selected
+      const enabledIds = stores.filter(s => s.enabled).map(s => s.id);
+      selectedStoreIds = new Set(enabledIds);
     } catch { /* server may not be ready yet */ }
   });
 
+  // Group stores by category
+  let storesByCategory = $derived(() => {
+    const enabledStores = stores.filter(s => s.enabled);
+    const grouped = new Map();
+
+    // Stores with a category
+    for (const cat of categories) {
+      const catStores = enabledStores.filter(s => s.category_id === cat.id);
+      if (catStores.length > 0) {
+        grouped.set(cat.id, { category: cat, stores: catStores });
+      }
+    }
+
+    // Stores without a category
+    const uncategorized = enabledStores.filter(s => !s.category_id);
+    if (uncategorized.length > 0) {
+      grouped.set(null, { category: { id: null, name: 'Other', color: '#6B7280' }, stores: uncategorized });
+    }
+
+    return [...grouped.values()];
+  });
+
+  // Check if all enabled stores are selected
+  $effect(() => {
+    const enabledIds = stores.filter(s => s.enabled).map(s => s.id);
+    allSelected = enabledIds.length > 0 && enabledIds.every(id => selectedStoreIds.has(id));
+  });
+
+  function toggleStore(id) {
+    const next = new Set(selectedStoreIds);
+    if (next.has(id)) next.delete(id); else next.add(id);
+    selectedStoreIds = next;
+  }
+
+  function toggleCategory(catId) {
+    const catStores = stores.filter(s => s.enabled && (catId === null ? !s.category_id : s.category_id === catId));
+    const catIds = catStores.map(s => s.id);
+    const allInCatSelected = catIds.every(id => selectedStoreIds.has(id));
+
+    const next = new Set(selectedStoreIds);
+    if (allInCatSelected) {
+      catIds.forEach(id => next.delete(id));
+    } else {
+      catIds.forEach(id => next.add(id));
+    }
+    selectedStoreIds = next;
+  }
+
+  function isCategorySelected(catId) {
+    const catStores = stores.filter(s => s.enabled && (catId === null ? !s.category_id : s.category_id === catId));
+    return catStores.length > 0 && catStores.every(s => selectedStoreIds.has(s.id));
+  }
+
+  function isCategoryPartial(catId) {
+    const catStores = stores.filter(s => s.enabled && (catId === null ? !s.category_id : s.category_id === catId));
+    const selected = catStores.filter(s => selectedStoreIds.has(s.id));
+    return selected.length > 0 && selected.length < catStores.length;
+  }
+
   function handleSearch(e) {
     e.preventDefault();
     if (!query.trim()) return;
 
+    const enabledIds = stores.filter(s => s.enabled).map(s => s.id);
     const params = new URLSearchParams({ q: query.trim() });
-    if (selectedCategory) params.set('category', selectedCategory);
+
-    if (selectedGroup) params.set('group', selectedGroup);
+    // Only pass store IDs if not all are selected
+    if (!allSelected && selectedStoreIds.size > 0) {
+      params.set('stores', [...selectedStoreIds].join(','));
+    }
 
     goto(`/results?${params}`);
   }
 </script>
 
 <div class="flex flex-col items-center justify-center min-h-full px-4">
-  <div class="w-full max-w-xl -mt-20">
+  <div class="w-full max-w-xl -mt-10">
     <div class="mb-8 text-center">
       <h1 class="text-3xl font-semibold text-text-primary mb-1.5">Price Hunter</h1>
       <p class="text-sm text-text-tertiary">Search across all your stores at once</p>
@@ -57,34 +123,67 @@
           Search
         </button>
       </div>
-
-      {#if categories.length > 0 || groups.length > 0}
-        <div class="flex gap-2 mt-3 justify-center">
-          {#if categories.length > 0}
-            <select
-              bind:value={selectedCategory}
-              class="input-field w-auto text-xs py-1.5 px-2.5"
-            >
-              <option value="">All categories</option>
-              {#each categories as cat}
-                <option value={cat.id}>{cat.name}</option>
-              {/each}
-            </select>
-          {/if}
-
-          {#if groups.length > 0}
-            <select
-              bind:value={selectedGroup}
-              class="input-field w-auto text-xs py-1.5 px-2.5"
-            >
-              <option value="">All groups</option>
-              {#each groups as group}
-                <option value={group.id}>{group.name}</option>
-              {/each}
-            </select>
-          {/if}
-        </div>
-      {/if}
     </form>
+
+    <!-- Store picker by category -->
+    {#if storesByCategory().length > 0}
+      <div class="mt-6 space-y-3">
+        {#each storesByCategory() as group}
+          <div>
+            <!-- Category header -->
+            <button
+              onclick={() => toggleCategory(group.category.id)}
+              class="flex items-center gap-2 mb-1.5 group/cat"
+            >
+              <span class="w-3 h-3 rounded-sm border flex items-center justify-center flex-shrink-0 transition-colors
+                {isCategorySelected(group.category.id)
+                  ? 'border-accent/50 bg-accent/20'
+                  : isCategoryPartial(group.category.id)
+                    ? 'border-accent/30 bg-accent/10'
+                    : 'border-text-tertiary/30'}">
+                {#if isCategorySelected(group.category.id)}
+                  <svg class="w-2 h-2 text-accent-text" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="3">
+                    <path stroke-linecap="round" stroke-linejoin="round" d="M4.5 12.75l6 6 9-13.5" />
+                  </svg>
+                {:else if isCategoryPartial(group.category.id)}
+                  <span class="w-1.5 h-0.5 bg-accent-text rounded-full"></span>
+                {/if}
+              </span>
+              <span class="text-2xs font-medium uppercase tracking-wider transition-colors
+                {isCategorySelected(group.category.id) ? 'text-text-secondary' : 'text-text-tertiary'}
+                group-hover/cat:text-text-primary"
+                style="color: {isCategorySelected(group.category.id) ? group.category.color : ''}">
+                {group.category.name}
+              </span>
+            </button>
+
+            <!-- Store chips -->
+            <div class="flex flex-wrap gap-1.5 pl-5">
+              {#each group.stores as store}
+                <button
+                  onclick={() => toggleStore(store.id)}
+                  class="flex items-center gap-1.5 text-2xs px-2 py-1 rounded border transition-colors duration-100
+                    {selectedStoreIds.has(store.id)
+                      ? 'bg-accent-muted border-accent/30 text-accent-text hover:bg-accent/20'
+                      : 'bg-surface border-surface-border text-text-tertiary line-through opacity-50 hover:opacity-75'}"
+                >
+                  <span class="w-3 h-3 rounded-sm border flex items-center justify-center flex-shrink-0
+                    {selectedStoreIds.has(store.id)
+                      ? 'border-accent/50 bg-accent/20'
+                      : 'border-text-tertiary/30'}">
+                    {#if selectedStoreIds.has(store.id)}
+                      <svg class="w-2 h-2 text-accent-text" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="3">
+                        <path stroke-linecap="round" stroke-linejoin="round" d="M4.5 12.75l6 6 9-13.5" />
+                      </svg>
+                    {/if}
+                  </span>
+                  {store.name}
+                </button>
+              {/each}
+            </div>
+          </div>
+        {/each}
+      </div>
+    {/if}
   </div>
 </div>