feat: split random into 'Was koche ich?' + 'Was backe ich?'

- Two dice buttons on homepage
- Cook: mittag, abend, fruehstueck categories
- Bake: backen, torten, desserts categories
- Backend: /api/recipes/random?categories=slug1,slug2 filter
- Luna's feature request

frontend/src/api/recipes.ts

@@ -24,8 +24,9 @@ export function fetchRecipe(slug: string) {
   return apiFetch<Recipe>(`/recipes/${slug}`)
 }
 
-export function fetchRandomRecipe() {
-  return apiFetch<Recipe>('/recipes/random')
+export function fetchRandomRecipe(categories?: string[]) {
+  const qs = categories ? `?categories=${categories.join(',')}` : ''
+  return apiFetch<Recipe>(`/recipes/random${qs}`)
 }
 
 export function searchRecipes(q: string) {

frontend/src/pages/HomePage.tsx

@@ -48,13 +48,18 @@ export function HomePage() {
     ? recipes.filter(r => r.tags?.includes(activeTag))
     : recipes
 
-  const handleRandomRecipe = async () => {
+    const handleRandomCook = async () => {
     try {
-      const recipe = await fetchRandomRecipe()
+      const recipe = await fetchRandomRecipe(['mittag', 'abend', 'fruehstueck'])
       if (recipe?.slug) navigate(`/recipe/${recipe.slug}?from=random`)
-    } catch {
-      // no recipes
-    }
+    } catch { /* no recipes */ }
+  }
+
+  const handleRandomBake = async () => {
+    try {
+      const recipe = await fetchRandomRecipe(['backen', 'torten', 'desserts'])
+      if (recipe?.slug) navigate(`/recipe/${recipe.slug}?from=random`)
+    } catch { /* no recipes */ }
   }
 
   const activeTags = (tags || []).filter(t => t.recipe_count > 0)
@@ -80,15 +85,22 @@ export function HomePage() {
         </motion.div>
       )}
 
-      {/* Random Recipe Button */}
+      {/* Random Recipe Buttons */}
       {totalCount > 1 && (
-        <div className="px-4 pb-4">
+        <div className="px-4 pb-4 flex gap-2">
           <button
-            onClick={handleRandomRecipe}
-            className="w-full bg-gradient-to-r from-primary to-secondary text-white px-4 py-3 rounded-2xl font-medium text-sm flex items-center justify-center gap-2 shadow-sm active:scale-[0.98] transition-transform min-h-[44px]"
+            onClick={handleRandomCook}
+            className="flex-1 bg-gradient-to-r from-primary to-secondary text-white px-3 py-3 rounded-2xl font-medium text-sm flex items-center justify-center gap-2 shadow-sm active:scale-[0.98] transition-transform min-h-[44px]"
           >
-            <Dices size={18} />
-            Was koche ich heute? 🎲
+            <Dices size={16} />
+            Was koche ich? 🥘
+          </button>
+          <button
+            onClick={handleRandomBake}
+            className="flex-1 bg-gradient-to-r from-secondary to-primary text-white px-3 py-3 rounded-2xl font-medium text-sm flex items-center justify-center gap-2 shadow-sm active:scale-[0.98] transition-transform min-h-[44px]"
+          >
+            <Dices size={16} />
+            Was backe ich? 🎂
           </button>
         </div>
       )}