docker: reduce unnecessary server image tooling

[jjj-n]

Description

Remove unnecessary tooling from the server image:

• stop installing make in the Go builder, which invokes go build directly;
• stop installing curl in the runtime image;
• replace the Docker Compose HTTP health check with a TCP check using Bash's /dev/tcp, matching the Helm chart probes.

Alternative implementation to #660. This version preserves the existing line endings, invokes Bash explicitly for /dev/tcp, and has been validated end to end with Docker Compose.

Fixes #659

Change Type

/kind cleanup

Changelog

NONE

Additional Notes

Validated by:

• building the complete server image;
• confirming git and bash remain available while curl and make are absent from the runtime;
• starting the Docker Compose stack and waiting for both PostgreSQL and AgentRegistry to become healthy;
• verifying /v0/ping returns {"pong":true};
• confirming the TCP check fails when no process is listening.

[jjj-n]

Hi maintainers, just following up on this server image cleanup for #659. The PR includes Docker Compose validation and uses a TCP health check in place of curl. Is this approach acceptable, or would you prefer any changes before review? Thanks!