refactor(planner): extract Suggestion type to $lib/planner/types.ts

Removes the inline interface from RecipePicker.svelte and replaces
any[] in +page.svelte with Suggestion[] — compile-time safety.

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

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

@@ -11,6 +11,7 @@
 	import BottomSheet from '$lib/components/BottomSheet.svelte';
 	import UndoBar from '$lib/planner/UndoBar.svelte';
 	import { prevWeek, nextWeek, getWeekStart, weekDays, formatDayLabel, formatDayAbbr, formatWeekRange, sortEasiestFirst } from '$lib/planner/week';
+	import type { Suggestion } from '$lib/planner/types';
 
 	let { data, form = null }: { data: { weekPlan: any; varietyScore: any; weekStart: string; recipes: any[] }; form?: any } = $props();
 
@@ -69,7 +70,7 @@
 		: null
 	);
 
-	let suggestions: any[] = $state([]);
+	let suggestions: Suggestion[] = $state([]);
 	let isLoadingSuggestions = $state(false);
 
 	// Recipes already in any slot this week — used for ⚠ overlap warnings