Phase 4: Documents & Memory — upload, FTS, AI tools, context injection

Backend:
- Document + MemoryEntry models with Alembic migration (GIN FTS index)
- File upload endpoint with path traversal protection (sanitized filenames)
- Background document text extraction (PyMuPDF)
- Full-text search on extracted_text via PostgreSQL tsvector/tsquery
- Memory CRUD with enum-validated categories/importance, field allow-list
- AI tools: save_memory, search_documents, get_memory (Claude function calling)
- Tool execution loop in stream_ai_response (multi-turn tool use)
- Context assembly: injects critical memory + relevant doc excerpts
- File storage abstraction (local filesystem, S3-swappable)
- Secure file deletion (DB flush before disk delete)

Frontend:
- Document upload dialog (drag-and-drop + file picker)
- Document list with status badges, search, download (via authenticated blob)
- Document viewer with extracted text preview
- Memory list grouped by category with importance color coding
- Memory editor with category/importance dropdowns
- Documents + Memory pages with full CRUD
- Enabled sidebar navigation for both sections

Review fixes applied:
- Sanitized upload filenames (path traversal prevention)
- Download via axios blob (not bare <a href>, preserves auth)
- Route ordering: /search before /{id}/reindex
- Memory update allows is_active=False + field allow-list
- MemoryEditor form resets on mode switch
- Literal enum validation on category/importance schemas
- DB flush before file deletion for data integrity

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/public/locales/ru/translation.json

@@ -90,6 +90,55 @@
     "subtitle": "Этот контекст добавляется ко всем вашим разговорам с ИИ",
     "placeholder": "Добавьте личную информацию, которую ИИ должен знать о вас..."
   },
+  "documents": {
+    "upload": "Загрузить",
+    "drop_or_click": "Перетащите файл или нажмите для выбора",
+    "doc_type": "Тип документа",
+    "no_documents": "Документы ещё не загружены.",
+    "download": "Скачать",
+    "reindex": "Извлечь текст заново",
+    "extracted_text": "Извлечённый текст",
+    "search_placeholder": "Поиск по документам...",
+    "clear_search": "Очистить",
+    "types": {
+      "other": "Другое",
+      "lab_result": "Анализы",
+      "consultation": "Консультация",
+      "prescription": "Рецепт",
+      "imaging": "Снимки"
+    },
+    "status": {
+      "pending": "Ожидание",
+      "processing": "Обработка",
+      "completed": "Готово",
+      "failed": "Ошибка"
+    }
+  },
+  "memory": {
+    "create": "Добавить запись",
+    "edit": "Редактировать запись",
+    "no_entries": "Записей пока нет. ИИ будет сохранять важную информацию о здоровье здесь.",
+    "category": "Категория",
+    "importance": "Важность",
+    "title_field": "Заголовок",
+    "title_placeholder": "напр. Диабет 2 типа",
+    "content_field": "Содержание",
+    "content_placeholder": "Подробная информация...",
+    "categories": {
+      "condition": "Заболевание",
+      "medication": "Лекарство",
+      "allergy": "Аллергия",
+      "vital": "Показатели",
+      "document_summary": "Сводка документа",
+      "other": "Другое"
+    },
+    "importance_levels": {
+      "critical": "Критическая",
+      "high": "Высокая",
+      "medium": "Средняя",
+      "low": "Низкая"
+    }
+  },
   "common": {
     "loading": "Загрузка...",
     "error": "Произошла ошибка",