fix: use authenticated user ID for habit service

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/routes/(app)/habits/+page.svelte

@@ -1,9 +1,10 @@
 <script lang="ts">
 	import type { HabitWithCompletions } from '$lib/context/habits.svelte';
+	import type { User } from 'better-auth';
 	import HabitGrid from './HabitGrid.svelte';
 	import HabitCreationForm from './HabitCreationForm.svelte';
 	import { setHabitService } from '$lib/context/habits.svelte';
-	
+
 	// shadcn-svelte components
 	import { Button } from '$lib/components/ui/button';
 	import * as Card from '$lib/components/ui/card';
@@ -12,7 +13,7 @@
 	import * as Popover from '$lib/components/ui/popover';
 	import * as Dialog from '$lib/components/ui/dialog';
 	import { Alert, AlertDescription } from '$lib/components/ui/alert';
-	
+
 	// Icons
 	import Plus from '@lucide/svelte/icons/plus';
 	import CalendarIcon from '@lucide/svelte/icons/calendar';
@@ -21,21 +22,24 @@
 	import AlertTriangle from '@lucide/svelte/icons/alert-triangle';
 	import Eye from '@lucide/svelte/icons/eye';
 	import EyeOff from '@lucide/svelte/icons/eye-off';
-	
+
 	import { today, getLocalTimeZone } from '@internationalized/date';
 	import { onMount } from 'svelte';
 
+	let { data }: { data: { user: User } } = $props();
+
 	let showCreateDialog = $state(false);
-	
+
 	// Date selection state
 	let selectedDate = $state(today(getLocalTimeZone()));
 	let showCalendar = $state(false);
-	
+
 	// Habit visibility toggle
 	let showInactiveHabits = $state(false);
-	
-	// Create habit service instance - subscriptions will handle all data loading
-	const habitService = setHabitService('default-user');
+
+	// Create habit service instance with authenticated user
+	// svelte-ignore state_referenced_locally
+	const habitService = setHabitService(data.user!.id);
 
 	// Simple loading state - just show skeleton briefly while subscriptions initialize
 	let loading = $state(true);