fix(detection+tandoor): handle stepless Instagram recipes

Many Instagram recipe posts list ingredients without preparation steps,
directing users to the 'link in bio' for the full recipe.

- Detection prompt: removed step requirement entirely — title + 2
  ingredients is sufficient to detect a recipe
- tandoor.ts: when steps array is null/empty, create a single
  placeholder step so all ingredients are preserved in Tandoor

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/lib/server/prompts/recipe-extraction.ts

@@ -9,19 +9,17 @@
 
 export const RECIPE_DETECTION_PROMPT = `You are a recipe detector for social media posts.
 
-Your task: Determine if the text contains a recipe or cooking instructions.
+Your task: Determine if the text contains recipe content (ingredients list, cooking info, or dish preparation).
 
-REQUIREMENTS FOR "YES" — text must have ALL of:
+SAY "yes" if the text has:
 1. A dish name or title
-2. At least 3 ingredients (quantities are NOT required — social media posts often omit them)
-3. At least 1 cooking or preparation step
+2. At least 2 ingredients (quantities optional — many posts omit them)
 
-IGNORE:
-- Hashtags (#recipe, #food, etc.)
-- Mentions (@username)
-- Emojis
-- Like counts, comments, social metadata
-- Promotional text ("follow me", "save this", "tag a friend")
+Steps are NOT required — many Instagram posts list only ingredients and link to the full recipe elsewhere.
+
+SAY "no" only if the text has NO ingredients at all (e.g. pure food appreciation posts, restaurant reviews, memes).
+
+IGNORE: hashtags, @mentions, emojis, "save this", "follow me", "link in bio" phrases.
 
 OUTPUT: Answer with ONLY 'yes' or 'no' - nothing else.
 
@@ -30,11 +28,14 @@ EXAMPLES:
 Text: "🍝 Pasta al Pomodoro Ingredients: pasta, tomatoes, garlic. Boil pasta. Sauté garlic. Add tomatoes. Mix! #italianfood @chef"
 Answer: yes
 
+Text: "Panini al Latte Ingredienti: 250g farina, 35g zucchero, 8g lievito, 130g latte, 1 uovo, 40g burro, gocce di cioccolato. Trovi la ricetta completa al link in bio."
+Answer: yes
+
 Text: "Amazing dinner tonight! 😍 So delicious! 🔥 #foodporn"
 Answer: no
 
-Text: "Brioche velocissime Per 7 brioche: rotolo di pasta sfoglia, prosciutto cotto, provola. Arrotola la sfoglia con i ripieni, taglia in pezzi, inforna a 180°C."
-Answer: yes
+Text: "Best restaurant in Milano! You have to try it 🙌"
+Answer: no
 `;
 
 export const RECIPE_EXTRACTION_PROMPT = `You are an EXPERT RECIPE EXTRACTOR specialized in parsing recipes from social media posts.

src/lib/server/tandoor.ts

@@ -234,10 +234,13 @@ function parseAmount(amountStr: string): number | null {
  * Includes ingredients partitioned across steps
  */
 function buildTandoorRecipeDTO(recipe: ExtractedRecipe): TandoorRecipeDTO {
-	const stepCount = recipe.steps?.length || 1;
+	// When the caption has no steps (e.g. "full recipe at link in bio"), create
+	// a single placeholder step so ingredients are preserved in Tandoor.
+	const recipeSteps = recipe.steps?.length ? recipe.steps : ['Vedi la ricetta completa al link in bio.'];
+	const stepCount = recipeSteps.length;
 	const ingredientPartitions = partitionIngredientsAcrossSteps(recipe.ingredients || [], stepCount);
 
-	const steps: TandoorRecipeDTO['steps'] = (recipe.steps || []).map((instruction, index) => {
+	const steps: TandoorRecipeDTO['steps'] = recipeSteps.map((instruction, index) => {
 		// Map ingredients, converting unparseable amounts to 1 q.b.
 		const mappedIngredients = (ingredientPartitions[index] || []).map((ing) => {
 			const amount = parseAmount(ing.amount);