feat: add Docker bootstrap for mcpd with auto-migration and seeding

Adds Dockerfile, entrypoint, and server bootstrap so that
`docker compose up` starts postgres, pushes the schema,
seeds default MCP servers, and starts mcpd with all routes wired up.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

deploy/docker-compose.yml

@@ -27,14 +27,17 @@ services:
       - "3100:3100"
     environment:
       DATABASE_URL: postgresql://mcpctl:mcpctl_dev@postgres:5432/mcpctl
-      PORT: "3100"
-      HOST: "0.0.0.0"
-      LOG_LEVEL: info
+      MCPD_PORT: "3100"
+      MCPD_HOST: "0.0.0.0"
+      MCPD_LOG_LEVEL: info
     depends_on:
       postgres:
         condition: service_healthy
     volumes:
-      - /var/run/docker.sock:/var/run/docker.sock
+      # Mount container runtime socket (Docker or Podman)
+      # For Docker: /var/run/docker.sock
+      # For Podman: /run/user/<UID>/podman/podman.sock
+      - ${CONTAINER_SOCK:-/var/run/docker.sock}:/var/run/docker.sock
     networks:
       - mcpctl
       - mcp-servers