fix zai context window (functionally [advertised context window] - [max output tokens]) and properly pass in max tokens so Z.ai doesn't default to 65k for GLM-5
* feat: add zai provider support
* add zai_api_key secret to deploy-core
* add to justfile
* add testing, provider integration skill
* enable zai key
* fix zai test
* clean up skill a little
* small changes