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/login/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { t } from 'svelte-i18n';
 	import { superForm } from 'sveltekit-superforms';
 	import type { PageData } from './$types.js';
 	import AmbientBackground from '$lib/components/background/AmbientBackground.svelte';
@@ -12,7 +13,7 @@
 </script>
 
 <svelte:head>
-	<title>Login — Web App Launcher</title>
+	<title>{$t('auth.login_submit')} — {$t('app_title')}</title>
 </svelte:head>
 
 <AmbientBackground />
@@ -37,8 +38,8 @@
 					<rect x="3" y="14" width="7" height="7" />
 				</svg>
 			</div>
-			<h1 class="text-2xl font-bold text-card-foreground">Welcome back</h1>
-			<p class="mt-1 text-sm text-muted-foreground">Sign in to your account</p>
+			<h1 class="text-2xl font-bold text-card-foreground">{$t('auth.login_title')}</h1>
+			<p class="mt-1 text-sm text-muted-foreground">{$t('auth.login_subtitle')}</p>
 		</div>
 
 		{#if showOAuthButton}
@@ -51,7 +52,7 @@
 					<polyline points="10 17 15 12 10 7" />
 					<line x1="15" y1="12" x2="3" y2="12" />
 				</svg>
-				Sign in with OAuth
+				{$t('auth.oauth_signin')}
 			</a>
 		{/if}
 
@@ -61,7 +62,7 @@
 					<div class="w-full border-t border-border"></div>
 				</div>
 				<div class="relative flex justify-center text-xs uppercase">
-					<span class="bg-card px-2 text-muted-foreground">or</span>
+					<span class="bg-card px-2 text-muted-foreground">{$t('auth.or')}</span>
 				</div>
 			</div>
 		{/if}
@@ -70,7 +71,7 @@
 			<form method="POST" use:enhance class="space-y-4">
 				<div>
 					<label for="email" class="mb-1 block text-sm font-medium text-card-foreground">
-						Email
+						{$t('auth.email')}
 					</label>
 					<input
 						id="email"
@@ -79,7 +80,7 @@
 						autocomplete="email"
 						bind:value={$form.email}
 						class="w-full rounded-lg border border-input bg-background px-3 py-2.5 text-sm text-foreground placeholder:text-muted-foreground transition-colors focus:border-primary focus:outline-none focus:ring-2 focus:ring-ring/30"
-						placeholder="you@example.com"
+						placeholder={$t('auth.email_placeholder')}
 					/>
 					{#if $errors.email}
 						<p class="mt-1 text-sm text-destructive">{$errors.email[0]}</p>
@@ -88,7 +89,7 @@
 
 				<div>
 					<label for="password" class="mb-1 block text-sm font-medium text-card-foreground">
-						Password
+						{$t('auth.password')}
 					</label>
 					<input
 						id="password"
@@ -97,7 +98,7 @@
 						autocomplete="current-password"
 						bind:value={$form.password}
 						class="w-full rounded-lg border border-input bg-background px-3 py-2.5 text-sm text-foreground placeholder:text-muted-foreground transition-colors focus:border-primary focus:outline-none focus:ring-2 focus:ring-ring/30"
-						placeholder="Enter your password"
+						placeholder={$t('auth.password_placeholder')}
 					/>
 					{#if $errors.password}
 						<p class="mt-1 text-sm text-destructive">{$errors.password[0]}</p>
@@ -112,10 +113,10 @@
 					{#if $submitting}
 						<span class="flex items-center justify-center gap-2">
 							<span class="h-4 w-4 animate-spin rounded-full border-2 border-primary-foreground border-t-transparent"></span>
-							Signing in...
+							{$t('auth.login_submitting')}
 						</span>
 					{:else}
-						Sign In
+						{$t('auth.login_submit')}
 					{/if}
 				</button>
 			</form>
@@ -123,8 +124,8 @@
 
 		{#if showLocalForm}
 			<p class="mt-6 text-center text-sm text-muted-foreground">
-				Don't have an account?
-				<a href="/register" class="font-medium text-primary hover:underline">Register</a>
+				{$t('auth.no_account')}
+				<a href="/register" class="font-medium text-primary hover:underline">{$t('auth.register')}</a>
 			</p>
 		{/if}
 	</div>