i18n: Translate all Chinese to English across the codebase

Translate Chinese comments, log/error messages, validator labels and
Swagger annotations to English throughout the source code, generated
Swagger docs, config files and CI workflows.

Make the English README primary: README.md now holds the English docs
and README_EN.md holds the Chinese version, with cross-language links
updated accordingly.

Note: the generated docs/ swagger files were translated in place; run
`go generate ./...` (swag init) to regenerate them from the now-English
annotations when a Go toolchain is available.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/cache/cache.go

@@ -10,7 +10,7 @@ type Handler interface {
 	Gc() error
 }
 
-// MaxTimeOut 最大超时时间
+// MaxTimeOut maximum timeout
 
 const (
 	TypeMem    = "memory"
@@ -49,7 +49,7 @@ func EncodeValue(value interface{}) (string, error) {
 }
 
 func DecodeValue(value string, rtv interface{}) error {
-	//判断rtv的类型是否是string，如果是string，直接赋值并返回
+	// check whether rtv's type is string; if so, assign directly and return
 	/*switch rtv.(type) {
 	case *string:
 		*(rtv.(*string)) = value