chore(systemd): remove obsolete systemd service files and update infrastructure documentation

- Remove 8 unused systemd service files from coordinator-api/systemd/
  - aitbc-adaptive-learning.service (port 8005)
  - aitbc-advanced-ai.service
  - aitbc-enterprise-api.service
  - aitbc-gpu-multimodal.service (port 8003)
  - aitbc-marketplace-enhanced.service (port 8006)
  - aitbc-modality-optimization.service (port 8004)
  - aitbc-multimodal.service (port 8002)
  - aitbc-openclaw-enhanced.service (port 8007

dev/service/stop-services.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+# Stop all AITBC services
+
+echo "🛑 Stopping AITBC Services"
+echo "========================"
+
+# Stop by PID if file exists
+if [ -f .service_pids ]; then
+    PIDS=$(cat .service_pids)
+    echo "Found PIDs: $PIDS"
+    for PID in $PIDS; do
+        if kill -0 $PID 2>/dev/null; then
+            echo "Stopping PID $PID..."
+            kill $PID
+        fi
+    done
+    rm -f .service_pids
+fi
+
+# Force kill any remaining services
+echo "Cleaning up any remaining processes..."
+sudo fuser -k 8000/tcp 2>/dev/null || true
+sudo fuser -k 9080/tcp 2>/dev/null || true
+sudo fuser -k 3001/tcp 2>/dev/null || true
+sudo fuser -k 3002/tcp 2>/dev/null || true
+pkill -f "uvicorn.*aitbc" 2>/dev/null || true
+pkill -f "server.py" 2>/dev/null || true
+
+echo "✅ All services stopped!"