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

internal/crd/v1alpha1/flink_job.go

@@ -1,7 +1,10 @@
 package v1alpha1
 
 import (
+	"encoding/json"
 	"errors"
+	"sort"
+	"strings"
 	"time"
 
 	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -9,6 +12,53 @@ import (
 
 //go:generate go run sigs.k8s.io/controller-tools/cmd/controller-gen object paths=$GOFILE
 
+// Args is a list of program arguments passed to the Flink job.
+// It accepts two formats in JSON/YAML:
+//
+//	List:  ["--kafka-host", "broker:9092", "--kafka-group-id", "my-group"]
+//	Map:   {kafka-host: "broker:9092", kafka-group-id: "my-group"}
+//
+// Map keys are automatically prefixed with "--" and expanded into alternating
+// key/value pairs. The internal representation is always a flat []string.
+type Args []string
+
+// UnmarshalJSON implements dual-format deserialization.
+func (a *Args) UnmarshalJSON(data []byte) error {
+	// Try map format first: {"key": "value", ...}
+	var m map[string]string
+	if err := json.Unmarshal(data, &m); err == nil {
+		*a = make(Args, 0, len(m)*2)
+		// Sort keys for deterministic ordering.
+		keys := make([]string, 0, len(m))
+		for k := range m {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for _, k := range keys {
+			*a = append(*a, "--"+k, m[k])
+		}
+		return nil
+	}
+
+	// Fall back to list format: ["--key", "value", ...]
+	var s []string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	*a = Args(s)
+	return nil
+}
+
+// MarshalJSON serializes Args in the compact map format.
+func (a Args) MarshalJSON() ([]byte, error) {
+	m := make(map[string]string, len(a)/2)
+	for i := 0; i < len(a)-1; i += 2 {
+		key := strings.TrimPrefix(a[i], "--")
+		m[key] = a[i+1]
+	}
+	return json.Marshal(m)
+}
+
 type FlinkJobSpec struct {
 	Key                     string          `json:"key"`
 	Name                    string          `json:"name"`
@@ -19,7 +69,7 @@ type FlinkJobSpec struct {
 	JarURIBasicAuthPassword *string         `json:"jarURIBasicAuthPassword"`
 	SavepointInterval       metaV1.Duration `json:"savepointInterval"`
 	EntryClass              string          `json:"entryClass"`
-	Args                    []string        `json:"args"`
+	Args                    Args            `json:"args,omitempty"`
 }
 
 type FlinkJobStatus struct {