Fix $state runtime error: rename rune stores to .svelte.ts

$state runes only work in .svelte and .svelte.ts files. The toasts and
theme stores used $state in plain .ts files, which compiled in dev but
crashed in production SSR. Renamed and updated all imports.

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

src/lib/components/Toast.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { fly } from 'svelte/transition';
-	import { getToasts, removeToast, type ToastType } from '$lib/stores/toasts.js';
+	import { getToasts, removeToast, type ToastType } from '$lib/stores/toasts.svelte.js';
 
 	const toasts = $derived(getToasts());
 

src/lib/utils/api.ts

@@ -1,4 +1,4 @@
-import { toast } from '$lib/stores/toasts.js';
+import { toast } from '$lib/stores/toasts.svelte.js';
 import { getSocketId } from '$lib/stores/socket.js';
 
 export type ApiResult<T = any> = {

src/routes/+layout.svelte

@@ -3,7 +3,7 @@
 	import type { Snippet } from 'svelte';
 	import { onMount } from 'svelte';
 	import { connectSocket, disconnectSocket } from '$lib/stores/socket.js';
-	import { initTheme, toggleTheme, getTheme } from '$lib/stores/theme.js';
+	import { initTheme, toggleTheme, getTheme } from '$lib/stores/theme.svelte.js';
 	import NotificationBell from '$lib/components/NotificationBell.svelte';
 	import SearchBar from '$lib/components/SearchBar.svelte';
 	import Toast from '$lib/components/Toast.svelte';

src/routes/admin/+page.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { api } from '$lib/utils/api.js';
-	import { toast } from '$lib/stores/toasts.js';
+	import { toast } from '$lib/stores/toasts.svelte.js';
 
 	let { data } = $props();
 

src/routes/admin/site/+page.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { api } from '$lib/utils/api.js';
-	import { toast } from '$lib/stores/toasts.js';
+	import { toast } from '$lib/stores/toasts.svelte.js';
 
 	let { data } = $props();
 

src/routes/boards/+page.svelte

@@ -3,7 +3,7 @@
 	import { page } from '$app/stores';
 	import { replaceState } from '$app/navigation';
 	import { api } from '$lib/utils/api.js';
-	import { toast } from '$lib/stores/toasts.js';
+	import { toast } from '$lib/stores/toasts.svelte.js';
 
 	let { data } = $props();
 

src/routes/boards/[boardId]/+page.svelte

@@ -6,7 +6,7 @@
 	import { getDueUrgency, getUrgencyClasses, formatDueDate } from '$lib/utils/due-date.js';
 	import { joinBoard, leaveBoard, onBoardEvent, offBoardEvent, getSocketId } from '$lib/stores/socket.js';
 	import { api } from '$lib/utils/api.js';
-	import { toast } from '$lib/stores/toasts.js';
+	import { toast } from '$lib/stores/toasts.svelte.js';
 	import CardModal from '$lib/components/CardModal.svelte';
 	import ActivityFeed from '$lib/components/ActivityFeed.svelte';
 	import BoardFilters from '$lib/components/BoardFilters.svelte';