Add menu item allergens, drop nav Help link, animate customizer price

- Menu items can now list allergens (shared catalog + join table),
  shown on the menu grid and item detail pages when applicable, and
  editable from the admin menu item form.
- Removed the top-nav "Help" link now that the footer links to it.
- The item customization page's price now uses the sliding
  AnimatedNumber, matching the basket line price.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/db/seed.ts

@@ -145,6 +145,29 @@ export const seedGhostKitchen = async (db: NodePgDatabase<typeof schema>) => {
     ])
     .returning()
 
+  const allergens = await db
+    .insert(schema.allergens)
+    .values([
+      { name: 'Gluten' },
+      { name: 'Dairy' },
+      { name: 'Eggs' },
+      { name: 'Soy' },
+      { name: 'Peanuts' },
+      { name: 'Tree nuts' },
+      { name: 'Sesame' },
+    ])
+    .returning()
+  const allergenByName = Object.fromEntries(
+    allergens.map((allergen) => [allergen.name, allergen]),
+  )
+
+  await db.insert(schema.menuItemAllergens).values([
+    { menuItemId: pizza.id, allergenId: allergenByName['Gluten'].id },
+    { menuItemId: pizza.id, allergenId: allergenByName['Dairy'].id },
+    { menuItemId: burger.id, allergenId: allergenByName['Gluten'].id },
+    { menuItemId: burger.id, allergenId: allergenByName['Sesame'].id },
+  ])
+
   return {
     brand,
     machineTags: {
@@ -156,6 +179,7 @@ export const seedGhostKitchen = async (db: NodePgDatabase<typeof schema>) => {
     machines: { prep1, oven1, grill1, assembly1 },
     menuItems: { pizza, burger },
     menuItemOptions: { pizza: pizzaOptions, burger: burgerOptions },
+    allergens,
   }
 }