fix(ci): install Linux beta build dependencies

[Chemaclass]

🤔 Background

Related #1383

Linux test jobs could fail when the beta installer built the standalone runner without its required optimizer.

💡 Changes

• Install the optimizer before Ubuntu and localized Ubuntu test jobs, using the existing build verification pins.
• Mount a static build of the same optimizer into the Alpine test container.
• Verify beta installation passes all six assertions without a skip on Ubuntu and Alpine, plus the full local gate and Ubuntu strict suite.