v0.1.32 - Mix Calculator search, ingredient categories, throughput tidy-up

Mix Calculator: searchable Mix Name picker (mirrors Throughput search)

Ingredients Editor: add manual Category column; used to order Mix Calculator output

Mix Calculator: surface formula-only mixes (no product yet) via -mix_id sentinel

Throughput: remove unused For order / For stock destination controls from composer

Editor change history: show timestamps in local time (stored UTC) instead of raw UTC

frontend/src/routes/ingredients/+page.svelte

@@ -3,6 +3,7 @@
   import { toast } from '$lib/toast';
   import AppSecondaryRailLayout from '$lib/components/navigation/AppSecondaryRailLayout.svelte';
   import ChangeHistoryModal from '$lib/components/editor/ChangeHistoryModal.svelte';
+  import CategoryCombobox from '$lib/components/editor/CategoryCombobox.svelte';
   import SortHeader from '$lib/table/SortHeader.svelte';
   import { TableController } from '$lib/table/table.svelte';
   import { formatNumber } from '$lib/format';
@@ -297,7 +298,7 @@
           </label>
           <label>
             <span>Category</span>
-            <input bind:value={newIngredient.category} list="ingredient-categories" placeholder="e.g. Grains" />
+            <CategoryCombobox bind:value={newIngredient.category} options={knownCategories} placeholder="e.g. Grains" inputId="new-ingredient-category" />
           </label>
           <label>
             <span>Rounding</span>
@@ -367,7 +368,7 @@
 
           <div class="cell">
             <span class="cell-label">Category</span>
-            <input bind:value={row.draft_category} list="ingredient-categories" placeholder="—" aria-label="Category" />
+            <CategoryCombobox bind:value={row.draft_category} options={knownCategories} placeholder="—" ariaLabel={`Category for ${row.name}`} />
           </div>
 
           <div class="cell">
@@ -443,12 +444,6 @@
     </div>
   </section>
 
-  <datalist id="ingredient-categories">
-    {#each knownCategories as category (category)}
-      <option value={category}></option>
-    {/each}
-  </datalist>
-
   {#if historyIngredient}
     <ChangeHistoryModal
       entityType="ingredient"