fix: update public-api Dockerfile Go version from 1.24 to 1.25

[ambient-code]

Summary

• Update public-api Dockerfile base image from go-toolset:1.24 to go-toolset:1.25 to match the go 1.25.0 requirement in go.mod
• This aligns with the operator Dockerfile which already uses go-toolset:1.25

Root Cause

The go.mod was updated to require Go 1.25.0, but the Dockerfile base image was not updated. With GOTOOLCHAIN=local set in the UBI image, automatic toolchain download is disabled, causing go mod download to fail.

Test plan

• CI build of the public-api Docker image succeeds
• Existing public-api tests pass

Closes #1278

---

🤖 Ambient Session

[ambient-code]

The public-api Dockerfile base image was using go-toolset:1.24 while go.mod requires go 1.25.0. Updated to go-toolset:1.25 to match — same version the operator Dockerfile already uses.

🤖 Session