Initial scaffold: generation-rule-only Crossplane Bucket example

Educational RunWhen CodeCollection that discovers Crossplane GCP
Bucket CRDs (storage.gcp.upbound.io/v1beta1) and generates one SLX
per bucket. Ships only generation rules and Jinja templates; the
runtime lives in rw-generic-codecollection/k8s-kubectl-cmd (already
loaded by the airgap runner).

Includes:
- codebundles/gcp-bucket-crossplane-health with generation rule + 3 templates
- docs/01..07 numbered training chapters with screenshot placeholders
- README, .gitignore

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -0,0 +1,25 @@
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+.venv/
+
+# Robot Framework artifacts
+output.xml
+log.html
+report.html
+
+# Workspace-builder / runwhen-local rendered output
+output/
+.cnb-cache/
+.rwl-cache/
+
+# Editors / OS
+.DS_Store
+.vscode/
+.idea/
+*.swp
+
+# Local secrets or scratch
+*.local
+*.local.yaml