feat: add KiCAD host connection configuration to kicad-mcp

Add KICAD_HOST and KICAD_PORT environment variables
for connecting to an existing KiCAD instance on the host.
Default to host.docker.internal:5555 for Docker Desktop compatibility.

💘 Generated with Crush

Assisted-by: GLM-4.7 via Crush <crush@charm.land>

docker-compose.yml

@@ -4,6 +4,8 @@ services:
   # ==========================================
 
   # KiCAD MCP - PCB design automation
+  # NOTE: Requires KiCAD to be installed on host machine
+  # The MCP server connects to an existing KiCAD instance via TCP
   kicad-mcp:
     build:
       context: ./vendor/KiCAD-MCP-Server
@@ -12,6 +14,8 @@ services:
     restart: unless-stopped
     environment:
       - NODE_ENV=production
+      - KICAD_HOST=${KICAD_HOST:-host.docker.internal}
+      - KICAD_PORT=${KICAD_PORT:-5555}
     command: ["node", "dist/index.js"]
     profiles:
       - dev