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>

http/controller/api/audit.go

@@ -14,12 +14,12 @@ type Audit struct {
 }
 
 // AuditConn
-// @Tags 审计
-// @Summary 审计连接
-// @Description 审计连接
+// @Tags audit
+// @Summary audit connection
+// @Description audit connection
 // @Accept  json
 // @Produce  json
-// @Param body body request.AuditConnForm true "审计连接"
+// @Param body body request.AuditConnForm true "audit connection"
 // @Success 200 {string} string ""
 // @Failure 500 {object} response.Response
 // @Router /audit/conn [post]
@@ -59,12 +59,12 @@ func (a *Audit) AuditConn(c *gin.Context) {
 }
 
 // AuditFile
-// @Tags 审计
-// @Summary 审计文件
-// @Description 审计文件
+// @Tags audit
+// @Summary audit file
+// @Description audit file
 // @Accept  json
 // @Produce  json
-// @Param body body request.AuditFileForm true "审计文件"
+// @Param body body request.AuditFileForm true "audit file"
 // @Success 200 {string} string ""
 // @Failure 500 {object} response.Response
 // @Router /audit/file [post]