feat: Session persistence with Redis + Draft management fixes

- Implement session management API (/api/v1/session/create, verify, logout)
- Add session restoration from localStorage on page reload
- Fix session_id priority when loading drafts (use current, not old from DB)
- Add unified_id and claim_id to wizard payload sent to n8n
- Add Docker volume for frontend HMR (Hot Module Replacement)
- Add comprehensive session logging for debugging

Components updated:
- backend/app/api/session.py (NEW) - Session management endpoints
- backend/app/main.py - Include session router
- frontend/src/components/form/Step1Phone.tsx v2.0 - Create session after SMS
- frontend/src/pages/ClaimForm.tsx v3.8 - Session restoration & priority fix
- frontend/src/components/form/StepWizardPlan.tsx v1.4 - Add unified_id/claim_id
- docker-compose.yml - Add frontend volume for live reload

Session flow:
1. User verifies phone -> session created in Redis (24h TTL)
2. session_token saved to localStorage
3. Page reload -> session restored automatically
4. Draft selected -> current session_id used (not old from DB)
5. Wizard submit -> unified_id, claim_id, session_id sent to n8n
6. Logout -> session removed from Redis & localStorage

Fixes:
- Session token not persisting after page reload
- unified_id missing in n8n webhook payload
- Old session_id from draft overwriting current session
- Frontend changes requiring container rebuild

docs/CODE4_FIXED.js

@@ -0,0 +1,77 @@
+// n8n Code node (Run Once) — prepare object for Redis
+const items = $input.all();
+
+// 1) Найти первый подходящий элемент с parsed.obj
+let main = null;
+for (const it of items) {
+  const j = it.json;
+  if (!j) continue;
+  // возможные места
+  if (j.parsed && j.parsed.obj) { main = j.parsed.obj; break; }
+  if (j.parsed && j.parsed.ok && j.parsed.obj) { main = j.parsed.obj; break; }
+  if (j.output) {
+    // если output — строка JSON
+    try {
+      const parsed = JSON.parse(j.output);
+      if (parsed && parsed.wizard_plan) { main = parsed; break; }
+    } catch (e) {}
+  }
+  if (j.json && j.json.wizard_plan) { main = j.json; break; }
+}
+if (!main) {
+  // последний шанс: взять items[0].json
+  main = items[0] ? (items[0].json || items[0]) : null;
+}
+if (!main) {
+  throw new Error('Не удалось найти parsed.obj в входных данных');
+}
+
+// 2) Гарантии структуры
+main.wizard_plan = main.wizard_plan || {};
+main.coverage_report = main.coverage_report || {};
+main.coverage_report.docs_received = main.coverage_report.docs_received || [];
+main.wizard_plan.risks = main.wizard_plan.risks || ['DOCS_STATUS_UNKNOWN','EXPECTATION_UNSET'];
+main.wizard_plan.deadlines = main.wizard_plan.deadlines || [
+  { type: 'USER_UPLOAD_TTL', duration_hours: 48 },
+  { type: 'USER_APPROVAL_TTL', duration_hours: 24 }
+];
+
+// 3) Добавить примерный документ (state/cities) — если ещё нет такого id
+const exampleId = 'example_state_cities_json';
+const already = main.coverage_report.docs_received.find(d => d.id === exampleId);
+if (!already) {
+  const exampleDoc = {
+    id: exampleId,
+    name: 'state_cities_example.json',
+    type: 'application/json',
+    uploaded_at: new Date().toISOString(),
+    content: {
+      state: 'California',
+      cities: ['Los Angeles', 'San Francisco', 'San Diego']
+    }
+  };
+  main.coverage_report.docs_received.push(exampleDoc);
+}
+
+// 4) session token / key
+// Получаем session_token из разных источников (приоритет: Edit Fields11 > Redis Trigger)
+const sessionToken = $('Edit Fields11').first().json.session_token 
+  || $('Redis Trigger').first().json.message.session_id
+  || null;
+
+// Если session_token недоступен, генерируем временный ключ
+if (!sessionToken) {
+  console.warn('⚠️ session_token не найден, используем временный ключ');
+}
+
+// Используем session_token для Redis ключа (claim_id будет сгенерирован позже)
+const redisKey = `ocr_events:${sessionToken || 'temp-' + Date.now()}`;
+
+// 5) Возвращаем объект для следующего Redis node
+return [{
+  json: {
+    redis_key: redisKey,
+    redis_value: main
+  }
+}];
+