v0.9.0

The course is now taught in Go. The complete Python course is preserved on the python branch and every URL it published still resolves.

🚀 Features

• Rewrite the course, the reference agent, and the evaluation harness in Go on ADK Go
• (evals) Add a standalone wire-only evaluator that reaches the agent over REST and A2A
• (observability) Replace MLflow with Grafana Tempo, Loki, and Alertmanager
• (content) Add streaming, incident run, platform operations, scale out, alerting, cost governance, and a Python-to-Go bridge
• (docs) Publish with Hugo and Hextra, with dark mode and no external asset hosts

🐛 Bug Fixes

• (docs) Preserve all 76 previously published URLs as aliases, gated by a released-URL ledger

♻️ Refactor

• (ci) Pin Pages deployment authority to exactly one job