feat(phase2): localization EN/RU + additional widget types

- Add svelte-i18n with 224 translation keys (English + Russian)
- Language switcher in header (EN/RU toggle, persists to localStorage)
- Extract all hardcoded strings from 37 component/page files
- Add 4 new widget types: Bookmark, Note (markdown), Embed (iframe), Status
- WidgetRenderer dispatches by type, WidgetGrid supports full-width widgets
- Type-specific config forms in board editor
- Install marked for markdown rendering

src/routes/apps/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { t } from 'svelte-i18n';
 	import type { PageData } from './$types.js';
 	import AppCard from '$lib/components/app/AppCard.svelte';
 	import AppForm from '$lib/components/app/AppForm.svelte';
@@ -9,16 +10,16 @@
 </script>
 
 <svelte:head>
-	<title>Apps — Web App Launcher</title>
+	<title>{$t('app.title')} — {$t('app_title')}</title>
 </svelte:head>
 
 <div class="p-6">
 	<div class="mx-auto max-w-6xl">
 		<div class="mb-6 flex items-center justify-between">
 			<div>
-				<h1 class="text-2xl font-bold text-foreground">App Registry</h1>
+				<h1 class="text-2xl font-bold text-foreground">{$t('app.title')}</h1>
 				<p class="mt-1 text-sm text-muted-foreground">
-					{data.apps.length} app{data.apps.length === 1 ? '' : 's'} registered
+					{$t('app.apps_registered', { values: { count: data.apps.length } })}
 				</p>
 			</div>
 			<button
@@ -26,13 +27,13 @@
 				onclick={() => (showForm = !showForm)}
 				class="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-primary-foreground transition-colors hover:bg-primary/90 focus:outline-none focus:ring-2 focus:ring-ring"
 			>
-				{showForm ? 'Cancel' : 'Add App'}
+				{showForm ? $t('common.cancel') : $t('app.add')}
 			</button>
 		</div>
 
 		{#if showForm}
 			<div class="mb-6 rounded-xl border border-border bg-card p-6 shadow-sm">
-				<h2 class="mb-4 text-lg font-semibold text-card-foreground">New App</h2>
+				<h2 class="mb-4 text-lg font-semibold text-card-foreground">{$t('app.new')}</h2>
 				<AppForm form={data.form} action="?/create" />
 			</div>
 		{/if}
@@ -43,7 +44,7 @@
 					href="/apps"
 					class="rounded-full border border-border px-3 py-1 text-sm text-muted-foreground transition-colors hover:bg-accent hover:text-foreground"
 				>
-					All
+					{$t('app.all_categories')}
 				</a>
 				{#each data.categories as category (category)}
 					<a
@@ -72,8 +73,8 @@
 					<line x1="12" y1="8" x2="12" y2="12" />
 					<line x1="12" y1="16" x2="12.01" y2="16" />
 				</svg>
-				<p class="text-lg">No apps registered yet.</p>
-				<p class="mt-1 text-sm">Click "Add App" to register your first application.</p>
+				<p class="text-lg">{$t('app.no_apps')}</p>
+				<p class="mt-1 text-sm">{$t('app.no_apps_hint')}</p>
 			</div>
 		{:else}
 			<div class="grid grid-cols-1 gap-4 sm:grid-cols-2 md:grid-cols-3 lg:grid-cols-4">