feat: channel affinity (#2669)

* feat: channel affinity

* feat: channel affinity -> model setting

* fix: channel affinity

* feat: channel affinity op

* feat: channel_type setting

* feat: clean

* feat: cache supports both memory and Redis.

* feat: Optimise ui/ux

* feat: Optimise ui/ux

* feat: Optimise codex usage ui/ux

* feat: Optimise ui/ux

* feat: Optimise ui/ux

* feat: Optimise ui/ux

* feat: If the affinitized channel fails and a retry succeeds on another channel, update the affinity to the successful channel

pkg/cachex/codec.go

@@ -0,0 +1,53 @@
+package cachex
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type ValueCodec[V any] interface {
+	Encode(v V) (string, error)
+	Decode(s string) (V, error)
+}
+
+type IntCodec struct{}
+
+func (c IntCodec) Encode(v int) (string, error) {
+	return strconv.Itoa(v), nil
+}
+
+func (c IntCodec) Decode(s string) (int, error) {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return 0, fmt.Errorf("empty int value")
+	}
+	return strconv.Atoi(s)
+}
+
+type StringCodec struct{}
+
+func (c StringCodec) Encode(v string) (string, error) { return v, nil }
+func (c StringCodec) Decode(s string) (string, error) { return s, nil }
+
+type JSONCodec[V any] struct{}
+
+func (c JSONCodec[V]) Encode(v V) (string, error) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+func (c JSONCodec[V]) Decode(s string) (V, error) {
+	var v V
+	if strings.TrimSpace(s) == "" {
+		return v, fmt.Errorf("empty json value")
+	}
+	if err := json.Unmarshal([]byte(s), &v); err != nil {
+		return v, err
+	}
+	return v, nil
+}