feat(planner): wire J4 swap flow — mobile action sheet + desktop inline panel

Mobile: DayMealCard tap opens MealActionSheet; Swap → SwapSuggestionsSheet
(BottomSheet + SwapSuggestionList, easiest-first). Empty slots still open
RecipePicker directly.

Desktop: recipe-picker panel detects swap context (slot has recipe) and
renders SwapSuggestionList; empty slots continue to show RecipePicker.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/(app)/planner/+page.svelte

@@ -6,9 +6,11 @@
 	import WeekStrip from '$lib/planner/WeekStrip.svelte';
 	import DayMealCard from '$lib/planner/DayMealCard.svelte';
 	import RecipePicker from '$lib/planner/RecipePicker.svelte';
+	import MealActionSheet from '$lib/planner/MealActionSheet.svelte';
+	import SwapSuggestionList from '$lib/planner/SwapSuggestionList.svelte';
 	import BottomSheet from '$lib/components/BottomSheet.svelte';
 	import UndoBar from '$lib/planner/UndoBar.svelte';
-	import { prevWeek, nextWeek, getWeekStart, weekDays, formatDayLabel, formatDayAbbr, formatWeekRange } from '$lib/planner/week';
+	import { prevWeek, nextWeek, getWeekStart, weekDays, formatDayLabel, formatDayAbbr, formatWeekRange, sortEasiestFirst } from '$lib/planner/week';
 
 	let { data, form = null }: { data: { weekPlan: any; varietyScore: any; weekStart: string; recipes: any[] }; form?: any } = $props();
 
@@ -55,8 +57,18 @@
 
 	let panelState = $state<PanelState>({ kind: 'idle' });
 
-	// Mobile bottom sheet for RecipePicker
+	// Mobile bottom sheet for RecipePicker (empty slot) and swap flow
 	let pickerOpen = $state(false);
+	let actionSheetOpen = $state(false);
+	let swapSheetOpen = $state(false);
+
+	// Recipes already in any slot this week — used for ⚠ overlap warnings
+	let currentWeekRecipeIds = $derived(
+		new Set<string>(slots.filter((s: any) => s.recipe?.id).map((s: any) => s.recipe.id))
+	);
+
+	// Recipes sorted easiest-first for the swap suggestion list
+	let sortedRecipes = $derived(sortEasiestFirst(data.recipes));
 
 	// Hidden form field bindings
 	let addPlanId = $state('');
@@ -126,6 +138,11 @@
 		deleteSlotFormEl.requestSubmit();
 	}
 
+	async function handleSwapPick(recipeId: string, recipeName: string) {
+		swapSheetOpen = false;
+		await handleRecipePick(recipeId, recipeName);
+	}
+
 	function closePanelToIdle() {
 		panelState = { kind: 'idle' };
 	}
@@ -205,7 +222,8 @@
 			isToday={selectedDay === today}
 			isSelected={true}
 			readonly={!isPlanner}
-			onaddrecipe={isPlanner ? () => (pickerOpen = true) : undefined}
+			onactionsheet={isPlanner && selectedSlot.recipe ? () => (actionSheetOpen = true) : undefined}
+			onaddrecipe={isPlanner && !selectedSlot.recipe ? () => (pickerOpen = true) : undefined}
 		/>
 	</div>
 
@@ -255,7 +273,7 @@
 		</div>
 	{/if}
 
-	<!-- Mobile RecipePicker in BottomSheet -->
+	<!-- Mobile: empty slot → RecipePicker -->
 	<BottomSheet open={pickerOpen} onclose={() => (pickerOpen = false)}>
 		<RecipePicker
 			planId={weekPlan?.id ?? ''}
@@ -267,6 +285,32 @@
 			onpick={handleRecipePick}
 		/>
 	</BottomSheet>
+
+	<!-- Mobile: meal exists → action sheet (Swap / Cook / View / Cancel) -->
+	<MealActionSheet
+		open={actionSheetOpen}
+		slot={selectedSlot}
+		onswap={() => { actionSheetOpen = false; swapSheetOpen = true; }}
+		oncancel={() => (actionSheetOpen = false)}
+	/>
+
+	<!-- Mobile: swap suggestions sheet -->
+	<BottomSheet open={swapSheetOpen} onclose={() => (swapSheetOpen = false)} height="70vh">
+		{@const replacingMeta = [
+			selectedSlot.recipe?.cookTimeMin ? `${selectedSlot.recipe.cookTimeMin} Min` : null,
+			selectedSlot.recipe?.effort ?? null
+		].filter(Boolean).join(' · ')}
+		<div style="padding: 16px;">
+			<SwapSuggestionList
+				replacingName={selectedSlot.recipe?.name ?? ''}
+				replacingMeta={replacingMeta || undefined}
+				recipes={sortedRecipes}
+				{currentWeekRecipeIds}
+				onpick={handleSwapPick}
+				oncancel={() => (swapSheetOpen = false)}
+			/>
+		</div>
+	</BottomSheet>
 </div>
 
 <!-- Desktop: 3-panel layout -->
@@ -472,11 +516,13 @@
 
 			{:else if panelState.kind === 'recipe-picker'}
 				{@const pickerDate = panelState.date}
+				{@const pickerSlot = slotMap[pickerDate] ?? null}
+				{@const isSwapContext = !!pickerSlot?.recipe}
 
 				<!-- Panel header with back/close button -->
 				<div class="mb-3 flex items-center justify-between">
 					<p class="font-[var(--font-sans)] text-[12px] font-medium uppercase tracking-wide text-[var(--color-text-muted)]">
-						Rezept wählen
+						{isSwapContext ? 'Gericht tauschen' : 'Rezept wählen'}
 					</p>
 					<button
 						type="button"
@@ -488,17 +534,33 @@
 					</button>
 				</div>
 
-				<div class="flex-1 overflow-y-auto -mx-4 -mb-4">
-					<RecipePicker
-						planId={weekPlan?.id ?? ''}
-						date={pickerDate}
-						dateLabel={formatDayLabel(pickerDate)}
-						currentVarietyScore={varietyScore?.score ?? 0}
-						suggestions={[]}
-						allRecipes={data.recipes}
-						onpick={handleRecipePick}
-					/>
-				</div>
+				{#if isSwapContext}
+					{@const replacingMeta = [
+						pickerSlot.recipe.cookTimeMin ? `${pickerSlot.recipe.cookTimeMin} Min` : null,
+						pickerSlot.recipe.effort ?? null
+					].filter(Boolean).join(' · ')}
+					<div class="flex-1 overflow-y-auto -mx-4 -mb-4 px-4">
+						<SwapSuggestionList
+							replacingName={pickerSlot.recipe.name}
+							replacingMeta={replacingMeta || undefined}
+							recipes={sortedRecipes}
+							{currentWeekRecipeIds}
+							onpick={handleRecipePick}
+						/>
+					</div>
+				{:else}
+					<div class="flex-1 overflow-y-auto -mx-4 -mb-4">
+						<RecipePicker
+							planId={weekPlan?.id ?? ''}
+							date={pickerDate}
+							dateLabel={formatDayLabel(pickerDate)}
+							currentVarietyScore={varietyScore?.score ?? 0}
+							suggestions={[]}
+							allRecipes={data.recipes}
+							onpick={handleRecipePick}
+						/>
+					</div>
+				{/if}
 			{/if}
 		</aside>
 	</div>