Restructure: Move services from root to unified repo

Moved updated services from /home/sam/development/ root into aboutme_chat_demo/:
- knowledge_service/ (with ChromaDB, gitea_scraper, FastAPI)
- langgraph_service/ (with LangGraph agent orchestration)
- airflow/ (with DAGs for scheduled ingestion)

All services now in single repo location.
Modular docker-compose files per service maintained.
Removed duplicate nested directories.
Updated files reflect latest working versions.

docker-compose.yml

@@ -3,7 +3,7 @@ services:
     image: postgres:15-alpine
     environment:
       POSTGRES_USER: sam
-      POSTGRES_PASSWORD: sam4jo 
+      POSTGRES_PASSWORD: sam4jo
       POSTGRES_DB: chat_demo
     ports:
       - "5432:5432"
@@ -11,18 +11,24 @@ services:
       - postgres_data:/var/lib/postgresql/data
     networks:
       - ai-mesh
+    restart: unless-stopped
+
   backend:
     build: ./backend
     ports:
       - "8000:8000"
     environment:
       DATABASE_URL: postgresql://sam:sam4jo@db:5432/chat_demo
+      LANGGRAPH_URL: http://langgraph-service:8090
     volumes:
       - ./backend:/app
     depends_on:
       - db
+      - langgraph-service
     networks:
       - ai-mesh
+    restart: unless-stopped
+
   frontend:
     build: ./frontend
     ports:
@@ -32,10 +38,15 @@ services:
       - /app/node_modules
     environment:
       - CHOKIDAR_USEPOLLING=true
+    depends_on:
+      - backend
     networks:
       - ai-mesh
+
 volumes:
   postgres_data:
+
 networks:
-      ai-mesh:
-        external: true
+  ai-mesh:
+    external: true
+