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/lib/components/search/SearchDialog.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+	import { t } from 'svelte-i18n';
 	import { search } from '$lib/stores/search.svelte.js';
 	import SearchResult from './SearchResult.svelte';
 
@@ -33,7 +34,7 @@
 		<div
 			class="w-full max-w-lg rounded-lg border border-border bg-popover shadow-2xl"
 			role="dialog"
-			aria-label="Search"
+			aria-label={$t('search.placeholder')}
 		>
 			<!-- Input -->
 			<div class="flex items-center gap-2 border-b border-border px-4 py-3">
@@ -54,7 +55,7 @@
 					bind:this={inputEl}
 					bind:value={search.query}
 					type="text"
-					placeholder="Search apps and boards..."
+					placeholder={$t('search.placeholder')}
 					class="flex-1 bg-transparent text-sm text-foreground placeholder:text-muted-foreground focus:outline-none"
 				/>
 				<kbd
@@ -76,17 +77,17 @@
 					<p class="py-6 text-center text-sm text-destructive">{search.error}</p>
 				{:else if search.query.length < 2}
 					<p class="py-6 text-center text-sm text-muted-foreground">
-						Type at least 2 characters to search
+						{$t('search.min_chars')}
 					</p>
 				{:else if search.results.length === 0}
 					<p class="py-6 text-center text-sm text-muted-foreground">
-						No results for "{search.query}"
+						{$t('search.no_results', { values: { query: search.query } })}
 					</p>
 				{:else}
 					{#if appResults.length > 0}
 						<div class="mb-2">
 							<p class="mb-1 px-3 text-xs font-medium uppercase tracking-wider text-muted-foreground">
-								Apps
+								{$t('search.apps')}
 							</p>
 							{#each appResults as result (result.id)}
 								<SearchResult {result} onselect={() => search.close()} />
@@ -97,7 +98,7 @@
 					{#if boardResults.length > 0}
 						<div>
 							<p class="mb-1 px-3 text-xs font-medium uppercase tracking-wider text-muted-foreground">
-								Boards
+								{$t('search.boards')}
 							</p>
 							{#each boardResults as result (result.id)}
 								<SearchResult {result} onselect={() => search.close()} />