recipes: overhaul nutrition editor UI and defer saves to form submission

- Nutrition mappings and global overwrites are now local-only until
  the recipe is saved, preventing premature DB writes on generate/edit
- Generate endpoint supports ?preview=true for non-persisting previews
- Show existing nutrition data immediately instead of requiring generate
- Replace raw checkboxes with Toggle component for global overwrites,
  initialized from existing NutritionOverwrite records
- Fix search dropdown readability (solid backgrounds, proper theming)
- Use fuzzy search (fzf-style) for manual nutrition ingredient lookup
- Swap ingredient display: German primary, English in brackets
- Allow editing g/u on manually mapped ingredients
- Make translation optional: separate save (FAB) and translate buttons
- "Vollständig neu übersetzen" now triggers actual full retranslation
- Show existing translation inline instead of behind a button
- Replace nord0 dark backgrounds with semantic theme variables

src/routes/api/[recipeLang=recipeLang]/nutrition/generate/[name]/+server.ts

@@ -4,7 +4,7 @@ import { dbConnect } from '$utils/db';
 import { isEnglish } from '$lib/server/recipeHelpers';
 import { generateNutritionMappings } from '$lib/server/nutritionMatcher';
 
-export const POST: RequestHandler = async ({ params, locals }) => {
+export const POST: RequestHandler = async ({ params, locals, url }) => {
 	await locals.auth();
 	await dbConnect();
 
@@ -19,6 +19,14 @@ export const POST: RequestHandler = async ({ params, locals }) => {
 	const ingredients = recipe.ingredients || [];
 	const translatedIngredients = recipe.translations?.en?.ingredients;
 
+	const newMappings = await generateNutritionMappings(ingredients, translatedIngredients);
+	const preview = url.searchParams.get('preview') === 'true';
+
+	// In preview mode, return pure auto-matches without saving (client merges manual edits)
+	if (preview) {
+		return json({ mappings: newMappings, count: newMappings.length });
+	}
+
 	// Preserve manually edited mappings
 	const existingMappings = recipe.nutritionMappings || [];
 	const manualMappings = new Map(
@@ -27,8 +35,6 @@ export const POST: RequestHandler = async ({ params, locals }) => {
 			.map((m: any) => [`${m.sectionIndex}-${m.ingredientIndex}`, m])
 	);
 
-	const newMappings = await generateNutritionMappings(ingredients, translatedIngredients);
-
 	// Merge: keep manual edits, use new auto-matches for the rest
 	const finalMappings = newMappings.map(m => {
 		const key = `${m.sectionIndex}-${m.ingredientIndex}`;

src/routes/api/nutrition/search/+server.ts

@@ -1,41 +1,48 @@
 import { json, type RequestHandler } from '@sveltejs/kit';
 import { NUTRITION_DB } from '$lib/data/nutritionDb';
 import { BLS_DB } from '$lib/data/blsDb';
+import { fuzzyScore } from '$lib/js/fuzzy';
 
-/** GET: Search BLS + USDA nutrition databases by name substring */
+/** GET: Search BLS + USDA nutrition databases by fuzzy name match */
 export const GET: RequestHandler = async ({ url }) => {
 	const q = (url.searchParams.get('q') || '').toLowerCase().trim();
 	if (q.length < 2) return json([]);
 
-	const results: { source: 'bls' | 'usda'; id: string; name: string; category: string; calories: number }[] = [];
+	const scored: { source: 'bls' | 'usda'; id: string; name: string; category: string; calories: number; score: number }[] = [];
 
-	// Search BLS first (primary)
+	// Search BLS (primary)
 	for (const entry of BLS_DB) {
-		if (results.length >= 30) break;
-		if (entry.nameDe.toLowerCase().includes(q) || entry.nameEn.toLowerCase().includes(q)) {
-			results.push({
+		const scoreDe = fuzzyScore(q, entry.nameDe.toLowerCase());
+		const scoreEn = entry.nameEn ? fuzzyScore(q, entry.nameEn.toLowerCase()) : 0;
+		const best = Math.max(scoreDe, scoreEn);
+		if (best > 0) {
+			scored.push({
 				source: 'bls',
 				id: entry.blsCode,
 				name: `${entry.nameDe}${entry.nameEn ? ` (${entry.nameEn})` : ''}`,
 				category: entry.category,
 				calories: entry.per100g.calories,
+				score: best,
 			});
 		}
 	}
 
-	// Then USDA
+	// Search USDA
 	for (const entry of NUTRITION_DB) {
-		if (results.length >= 40) break;
-		if (entry.name.toLowerCase().includes(q)) {
-			results.push({
+		const s = fuzzyScore(q, entry.name.toLowerCase());
+		if (s > 0) {
+			scored.push({
 				source: 'usda',
 				id: String(entry.fdcId),
 				name: entry.name,
 				category: entry.category,
 				calories: entry.per100g.calories,
+				score: s,
 			});
 		}
 	}
 
-	return json(results.slice(0, 30));
+	// Sort by score descending, return top 30 (without score field)
+	scored.sort((a, b) => b.score - a.score);
+	return json(scored.slice(0, 30).map(({ score, ...rest }) => rest));
 };