feat: initial microservices project structure

Services:
- api: FastAPI gateway with JWT auth, async endpoints, WebSocket
- worker-gpu: CUDA sentence-transformers, FAISS IVFFlat, Ollama LLM
- worker-indexer: Winnowing+MinHash plagiarism detection, PDF/DOCX extraction
- worker-notifier: SMTP email notifications
- worker-gost: GOST 7.1-2003 and GOST R 7.0.5-2008 formatting

Infrastructure:
- docker-compose.yml (production) + docker-compose.dev.yml (hot reload)
- Nginx reverse proxy + WebSocket support
- PostgreSQL 16 with Alembic migrations
- Elasticsearch 8 with Russian/English analyzers
- MinIO, RabbitMQ, Redis, Ollama

Frontend:
- React 18 + Vite + TypeScript + TailwindCSS + Zustand + React Query v5
- 9 pages: Home, Search, Cabinet, Task, Check, Bibliography, Pricing, Login, Register

Scripts:
- Parser stubs: OpenAlex, КиберЛенинка, arXiv (Phase 0 - to be filled)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

services/frontend/src/hooks/useTaskPolling.ts

@@ -0,0 +1,52 @@
+import { useEffect, useRef } from 'react';
+import { useQueryClient } from '@tanstack/react-query';
+import type { Task } from '../types';
+
+/**
+ * Хук для WebSocket подключения к задаче.
+ * Обновляет кэш React Query при получении обновления статуса.
+ */
+export function useTaskWebSocket(taskId: string | undefined, enabled: boolean) {
+  const queryClient = useQueryClient();
+  const wsRef = useRef<WebSocket | null>(null);
+
+  useEffect(() => {
+    if (!taskId || !enabled) return;
+
+    const wsUrl = `${window.location.protocol === 'https:' ? 'wss' : 'ws'}://${window.location.host}/ws/tasks/${taskId}`;
+    const ws = new WebSocket(wsUrl);
+    wsRef.current = ws;
+
+    ws.onmessage = (event) => {
+      try {
+        const data = JSON.parse(event.data);
+        if (data === 'pong') return;
+
+        // Обновить кэш задачи
+        queryClient.setQueryData<Task>(['task', taskId], (old) => {
+          if (!old) return old;
+          return { ...old, ...data };
+        });
+      } catch (e) {
+        console.warn('Ошибка парсинга WebSocket сообщения:', e);
+      }
+    };
+
+    ws.onerror = () => {
+      console.warn(`WebSocket ошибка для задачи ${taskId}`);
+    };
+
+    // Keepalive ping каждые 30 секунд
+    const pingInterval = setInterval(() => {
+      if (ws.readyState === WebSocket.OPEN) {
+        ws.send('ping');
+      }
+    }, 30000);
+
+    return () => {
+      clearInterval(pingInterval);
+      ws.close();
+      wsRef.current = null;
+    };
+  }, [taskId, enabled, queryClient]);
+}