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/api.ts

@@ -279,6 +279,12 @@ export function listProxyRoutes(): Promise<ProxyRoute[]> {
 
 // ── Docker Management ──────────────────────────────────────────────
 
+export function fetchContainerLogs(
+	projectId: string, stageId: string, instanceId: string, tail = 200
+): Promise<string[]> {
+	return get<string[]>(`/api/projects/${projectId}/stages/${stageId}/instances/${instanceId}/logs?tail=${tail}`);
+}
+
 export function listProjectImages(projectId: string): Promise<LocalImage[]> {
 	return get<LocalImage[]>(`/api/projects/${projectId}/images`);
 }