Vibecoding course and ambient assessment AI

What changed

• The Vibecoding course split into its own served surface with textbook chapters, slides, labs, rubrics, syllabus, and project checkpoints.
• Assessment AI shifted toward ambient browser validation, validator loops, and multi-agent defaults.
• Token-spend evidence, model allowlists, stronger judge models, and brownfield question specs tightened how AI-assisted work is graded.