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/lib/components/Toggle.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-	let { checked = $bindable(false), label = "", accentColor = "var(--color-primary)", href = undefined as string | undefined } = $props<{ checked?: boolean, label?: string, accentColor?: string, href?: string }>();
+	let { checked = $bindable(false), label = "", accentColor = "var(--color-primary)", href = undefined as string | undefined, onchange = undefined as (() => void) | undefined } = $props<{ checked?: boolean, label?: string, accentColor?: string, href?: string, onchange?: () => void }>();
 </script>
 
 <style>
@@ -96,7 +96,7 @@
 		</a>
 	{:else}
 		<label>
-			<input type="checkbox" bind:checked />
+			<input type="checkbox" bind:checked onchange={onchange} />
 			<span>{label}</span>
 		</label>
 	{/if}

src/lib/components/recipes/TranslationApproval.svelte

@@ -14,7 +14,6 @@
 		onapproved?: (event: CustomEvent) => void;
 		onskipped?: () => void;
 		oncancelled?: () => void;
-		onforceFullRetranslation?: () => void;
 	}
 
 	let {
@@ -26,7 +25,6 @@
 		onapproved,
 		onskipped,
 		oncancelled,
-		onforceFullRetranslation
 	}: Props = $props();
 
 	type TranslationState = 'idle' | 'translating' | 'preview' | 'approved' | 'error';
@@ -204,7 +202,7 @@
 	});
 
 	// Handle auto-translate button click
-	async function handleAutoTranslate() {
+	async function handleAutoTranslate(fullRetranslation = false) {
 		translationState = 'translating';
 		errorMessage = '';
 		validationErrors = [];
@@ -217,7 +215,7 @@
 				},
 				body: JSON.stringify({
 					recipe: germanData,
-					fields: isEditMode && changedFields.length > 0 ? changedFields : undefined,
+					fields: isEditMode && !fullRetranslation && changedFields.length > 0 ? changedFields : undefined,
 					oldRecipe: oldRecipeData, // For granular item-level change detection
 					existingTranslation: englishData, // To merge with unchanged items
 				}),
@@ -358,11 +356,6 @@
 		oncancelled?.();
 	}
 
-	// Handle force full retranslation
-	function handleForceFullRetranslation() {
-		onforceFullRetranslation?.();
-	}
-
 	// Get status badge color
 	function getStatusColor(status: string): string {
 		switch (status) {
@@ -921,10 +914,10 @@ button:disabled {
 				<button class="btn-danger" onclick={handleCancel}>
 					Cancel
 				</button>
-				<button class="btn-secondary" onclick={handleForceFullRetranslation}>
+				<button class="btn-secondary" onclick={() => handleAutoTranslate(true)}>
 					Vollständig neu übersetzen
 				</button>
-				<button class="btn-secondary" onclick={handleAutoTranslate}>
+				<button class="btn-secondary" onclick={() => handleAutoTranslate()}>
 					Re-translate
 				</button>
 				<button class="btn-primary" onclick={handleApprove}>