feat: add /version endpoint and global Minder-Version header

[DharunMR]

Summary

This PR addresses the need to easily expose the Minder server's build version and commit hash for tooling and debugging purposes, as requested. It introduces a dedicated, unauthenticated /api/v1/version endpoint and adds a global gRPC Unary Interceptor to stamp the server version on all incoming HTTP/gRPC responses.

• Fixes Add a "/version" endpoint for Minder server #4048

Changes Included

• Protobuf: Added GetVersion RPC to HealthService mapped to GET /api/v1/version. Configured rpc_options to allow unauthenticated access (TARGET_RESOURCE_NONE).
• Server Handler: Implemented the GetVersion logic to return constants.CLIVersion and constants.Revision.
• Global Header: Created VersionHeaderInterceptor to inject the Minder-Version header into the response metadata for all requests.
• Telemetry Fix: Replaced the hardcoded "v0.1.0" service version in initMetrics with the dynamic constants.CLIVersion.

How I Tested This

1. Verified the new endpoint returns the correct JSON payload and header:
   curl -i http://localhost:8080/api/v1/version
2. Verified that the global header is successfully injected into other pre-existing endpoints:
   curl -I http://localhost:8080/api/v1/health

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[coveralls]

Coverage is 60.398% — DharunMR:add-version-endpoint into mindersec:main. No base build found for mindersec:main.

[evankanderson]

RFC 6648 deprecates the "X-" prefix on headers, so just call this either "minder-version" or "server" (a standard header). If you use server, you might want to include the string "Minder" before the version.

[evankanderson]

In fact, constants.ServerUserAgent might be exactly what you want.

Note that constants.CLIVersion only appears to be set via ldflags for CLI builds, not for the server. The Makefile and GitHub Actions is probably the right place to do this if you want to; you'll need to use GOFLAGS per https://ko.build/advanced/faq/#how-can-i-set-ldflags

[DharunMR]

thanks for pointing me toward GOFLAGS the server binary now correctly stamp the version

is commit hash required ??

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