Speed up Coolify deployments

[Loa212]

What changed

• remove build: . from the installation Compose service so deployments pull ghcr.io/loa212/nudo:latest
• set pull_policy: always so redeployments check for the latest release image
• add .dockerignore entries for Rust build output, local state, repository metadata, and files unused by the image build

Why

The Compose file specified both build: . and image:. Docker Compose therefore treated the image name as the tag for a locally built image, causing Coolify to compile the full Rust release workspace instead of pulling the image already published by the release workflow. Those cold builds took roughly ten minutes.

The missing .dockerignore could also send large local artifacts into manual Docker builds; this checkout had a 38 GB target/ directory.

Impact

Coolify and other production Compose deployments now use the prebuilt GHCR image. Intentional source builds remain available through the Dockerfile for development, CI, and releases.

Validation

• NUDO_SECRET_KEY=validation-only docker compose config --quiet
• verified docker compose config --images resolves only to ghcr.io/loa212/nudo:latest
• git diff --cached --check