feat(crd): add dual-format Args field supporting map and list

Add a custom Args type that accepts both a key-value map and a flat
CLI-style list, normalizing internally to []string so downstream code
requires no changes.

- Args: new []string alias with UnmarshalJSON (map + list) and
  MarshalJSON (map) — keys are sorted for deterministic ordering
- CRD schema: switch args from typed array to
  x-kubernetes-preserve-unknown-fields to accept either shape
- Bump go-flink-client to v0.2.2 (fix: programArgsList → programArg
  query parameter name for Flink REST API)

Args can now be written as:
  args:
    kafka-host: broker:9092
    kafka-group-id: my-group

Or the existing list format:
  args:
    - "--kafka-host"
    - broker:9092

helm/chart/values.yaml

@@ -11,7 +11,7 @@ image:
   # This sets the pull policy for images.
   pullPolicy: Always
   # Overrides the image tag whose default is the chart appVersion.
-  tag: v1.3.0
+  tag: v1.3.1
 
 # This is for the secretes for pulling an image from a private repository more information can be found here: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/
 imagePullSecrets: []