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/section/Section.svelte

@@ -29,11 +29,22 @@
 		widgets: WidgetData[];
 	}
 
-	interface Props {
-		section: SectionData;
+	interface AppData {
+		id: string;
+		name: string;
+		url: string;
+		icon: string | null;
+		iconType: string;
+		description: string | null;
+		statuses: Array<{ status: string; responseTime: number | null }>;
 	}
 
-	let { section }: Props = $props();
+	interface Props {
+		section: SectionData;
+		allApps?: AppData[];
+	}
+
+	let { section, allApps = [] }: Props = $props();
 
 	let expanded = $state(section.isExpandedByDefault);
 </script>
@@ -48,7 +59,7 @@
 
 	<SectionCollapsible {expanded}>
 		<div class="px-4 pb-4">
-			<WidgetGrid widgets={section.widgets} />
+			<WidgetGrid widgets={section.widgets} {allApps} />
 		</div>
 	</SectionCollapsible>
 </div>