muster release v5.31.2

muster-crds accepts any CRD annotation, and CI runs its chart tests. The loader merges every key of crds.annotations into each CRD, but the generated values.schema.json admitted only helm.sh/resource-policy, so any other annotation failed the install with additional properties ... not allowed. The schema now takes any key with a string value and refuses a non-string one, which the API server would reject. make helm-unittest (the chart-test job) ran the muster chart’s suites only; it now runs the muster-crds suite as well, updated to the three CRDs the chart ships and the current Workflow CEL rules. NOTES.txt and UPGRADE.md name the WorkflowExecution CRD too. (#1324)