feat(docker-watcher): phase 14 - frontend polish & modern UI

Design system with CSS custom properties (light/dark themes).
38 Lucide SVG icon components. Dark mode with system preference.
EN/RU localization with i18n store. Skeleton loaders, empty states,
toggle switches, micro-interactions. Responsive sidebar with
mobile hamburger menu. All pages polished with consistent styling.

web/src/lib/components/icons/IconShield.svelte

@@ -0,0 +1,7 @@
+<script lang="ts">
+	interface Props { size?: number; class?: string; }
+	const { size = 20, class: c = '' }: Props = $props();
+</script>
+<svg xmlns="http://www.w3.org/2000/svg" width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" class={c} aria-hidden="true">
+	<path d="M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z" />
+</svg>