Update dev container workspace path and mounting configuration

Moves the workspace volume mount from the docker-compose file to devcontainer.json and standardizes the workspace path to /workspace.

.devcontainer/docker-compose.devcontainer.yml

@@ -4,8 +4,6 @@ services:
   workspace:
     image: mcr.microsoft.com/devcontainers/javascript-node:1-20-bookworm
     command: sleep infinity
-    volumes:
-      - ..:/workspaces/fog:cached
     depends_on:
       postgres:
         condition: service_healthy