Instruct Copilot to build Calcite from source when setting up its work environment

When implementing a feature in the SQL compiler, Copilot got confused by the version mismatch of Calcite dependency and spent 12 minutes until it realized it needs to build it from source. Instructions in .github/copilot-instructions.md did not seem to avoid this.

Copilot needs to be instructed to build Calcite from source.