[DX] Improve local development experience with Docker Compose

[wnqueiroz]

Context

While testing Crossview locally with a kind cluster, I found the manual setup process harder than it should be for new contributors. Getting everything running requires:

• installing Go and Node.js at the right versions
• spinning up a PostgreSQL instance separately
• managing multiple terminal sessions (frontend dev server, backend, DB)
• dealing with kubeconfig quirks when the K8s API server address resolves differently inside containers vs. on the host

This friction slows onboarding and creates an inconsistent dev environment across machines. A more plug-and-play setup would lower the barrier to contribution significantly.

What we want

• Single command to start the full local stack (frontend + backend + database)
• Backend live reload on Go source file changes, without restarting the container
• Frontend hot module replacement without manual restarts
• PostgreSQL provisioned automatically (no separate installation required)
• Host kubeconfig accessible inside dev containers for cluster interactions
• Support for kind (and similar) clusters where the API server address must be overridden from inside the container network
• Local environment overrides via a gitignored .env file at the project root
• Simple, memorable commands to start and tear down the environment

Expected outcome

A contributor can clone the repo, run a single command, and have a fully functional development environment with hot reload on both frontend and backend, including connectivity to a local kind cluster.