Buildkite badges

### 📋 Description

For Buildkite.

### 🔗 Data

https://buildkite.com/docs/apis/rest-api/annotations
https://buildkite.com/docs/apis/rest-api/annotations#create-an-annotation-on-a-build
https://buildkite.com/docs/pipelines/notifications#build-states
https://buildkite.com/docs/apis/rest-api/pipeline-templates
https://buildkite.com/docs/apis/agent-api/metrics#get-metrics

### 🎤 Motivation

Add dynamic badges for not yet implemented buildkite API data.

Start by reviewing the linked Buildkite annotation, pipeline-template, notification, and agent-metrics API documentation. The issue does not name repository files, tests, or an entry point, so the implementation scope must be clarified first; done would mean dynamic badges for the requested Buildkite API data.

Written by the indexing model from the issue text.