feat: container logs viewer with SSE streaming and line limiter

- Add GET /api/projects/{id}/stages/{stage}/instances/{iid}/logs endpoint
- Supports JSON mode (returns array of lines) and SSE mode (streams in real-time)
- Docker log stream header (8-byte prefix) stripped automatically
- ContainerLogs component with:
  - Tail line selector (50/200/500/1000)
  - Follow button for real-time streaming via SSE
  - Auto-scroll to bottom
  - Dark terminal-style display
  - Close button
- Logs button (events icon) on each instance card
- i18n keys in EN and RU

web/src/lib/components/InstanceCard.svelte

@@ -5,8 +5,9 @@
 	import type { Instance } from '$lib/types';
 	import StatusBadge from './StatusBadge.svelte';
 	import ContainerStats from './ContainerStats.svelte';
+	import ContainerLogs from './ContainerLogs.svelte';
 	import ConfirmDialog from './ConfirmDialog.svelte';
-	import { IconPlay, IconStop, IconRestart, IconTrash, IconExternalLink } from '$lib/components/icons';
+	import { IconPlay, IconStop, IconRestart, IconTrash, IconExternalLink, IconEvents } from '$lib/components/icons';
 	import { t } from '$lib/i18n';
 	import * as api from '$lib/api';
 
@@ -22,6 +23,7 @@
 	let loading = $state(false);
 	let error = $state('');
 	let confirmAction = $state<'stop' | 'restart' | 'remove' | null>(null);
+	let showLogs = $state(false);
 
 	const subdomainUrl = $derived(
 		instance.subdomain && domain
@@ -133,6 +135,14 @@
 					<IconPlay size={16} />
 				</button>
 			{/if}
+			<button
+				type="button"
+				class="rounded-lg p-2 text-[var(--text-tertiary)] hover:bg-gray-100 hover:text-gray-600 dark:hover:bg-gray-800 dark:hover:text-gray-300 transition-all duration-150"
+				title={$t('logs.title')}
+				onclick={() => { showLogs = !showLogs; }}
+			>
+				<IconEvents size={16} />
+			</button>
 			<button
 				type="button"
 				class="rounded-lg p-2 text-[var(--text-tertiary)] hover:bg-red-50 hover:text-red-600 disabled:opacity-50 transition-all duration-150 active:animate-press"
@@ -149,6 +159,17 @@
 		<ContainerStats projectId={projectId} stageId={instance.stage_id} instanceId={instance.id} />
 	{/if}
 
+	{#if showLogs}
+		<div class="mt-2">
+			<ContainerLogs
+				{projectId}
+				stageId={instance.stage_id}
+				instanceId={instance.id}
+				onclose={() => { showLogs = false; }}
+			/>
+		</div>
+	{/if}
+
 	{#if error}
 		<p class="mt-2 text-xs text-[var(--color-danger)]">{error}</p>
 	{/if}