feat: implement RAG Service MVP with PARSER + Memory integration

RAG Service Implementation:
- Create rag-service/ with full structure (config, document_store, embedding, pipelines)
- Document Store: PostgreSQL + pgvector via Haystack
- Embedding: BAAI/bge-m3 (multilingual, 1024 dim)
- Ingest Pipeline: Convert ParsedDocument to Haystack Documents, embed, index
- Query Pipeline: Retrieve documents, generate answers via DAGI Router
- FastAPI endpoints: /ingest, /query, /health

Tests:
- Unit tests for ingest and query pipelines
- E2E test with example parsed JSON
- Test fixtures with real PARSER output example

Router Integration:
- Add mode='rag_query' routing rule in router-config.yml
- Priority 7, uses local_qwen3_8b for RAG queries

Docker:
- Add rag-service to docker-compose.yml
- Configure dependencies (router, city-db)
- Add model cache volume

Documentation:
- Complete README with API examples
- Integration guides for PARSER and Router

services/rag-service/tests/test_e2e.py

@@ -0,0 +1,67 @@
+"""
+E2E tests for RAG Service
+Tests full ingest → query pipeline
+"""
+
+import pytest
+import json
+from pathlib import Path
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+client = TestClient(app)
+
+# Load example parsed JSON
+FIXTURES_DIR = Path(__file__).parent / "fixtures"
+EXAMPLE_JSON = json.loads((FIXTURES_DIR / "parsed_json_example.json").read_text())
+
+
+class TestE2E:
+    """End-to-end tests"""
+    
+    def test_health(self):
+        """Test health endpoint"""
+        response = client.get("/health")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["status"] == "healthy"
+        assert data["service"] == "rag-service"
+    
+    @pytest.mark.skip(reason="Requires database connection")
+    def test_ingest_then_query(self):
+        """Test full pipeline: ingest → query"""
+        # Step 1: Ingest document
+        ingest_request = {
+            "dao_id": "daarion",
+            "doc_id": "microdao-tokenomics-2025-11",
+            "parsed_json": EXAMPLE_JSON
+        }
+        
+        ingest_response = client.post("/ingest", json=ingest_request)
+        assert ingest_response.status_code == 200
+        ingest_data = ingest_response.json()
+        assert ingest_data["status"] == "success"
+        assert ingest_data["doc_count"] > 0
+        
+        # Step 2: Query
+        query_request = {
+            "dao_id": "daarion",
+            "question": "Поясни токеноміку microDAO і роль стейкінгу"
+        }
+        
+        query_response = client.post("/query", json=query_request)
+        assert query_response.status_code == 200
+        query_data = query_response.json()
+        
+        assert "answer" in query_data
+        assert len(query_data["answer"]) > 0
+        assert "citations" in query_data
+        assert len(query_data["citations"]) > 0
+        
+        # Check citation structure
+        citation = query_data["citations"][0]
+        assert "doc_id" in citation
+        assert "page" in citation
+        assert "excerpt" in citation
+