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>

conf/config.yaml

@@ -1,18 +1,18 @@
 lang: "zh-CN"
 app:
-  web-client: 1  # 1:启用 0:禁用
-  register: false #是否开启注册
-  register-status: 1 # 注册用户默认状态 1:启用 2:禁用
+  web-client: 1  # 1:enable 0:disable
+  register: false #whether registration is enabled
+  register-status: 1 # default status for registered users 1:enable 2:disable
   captcha-threshold: 3 #   <0:disabled, 0 always, >0:enabled
   ban-threshold: 0 # 0:disabled, >0:enabled
-  show-swagger: 0 # 1:启用 0:禁用
+  show-swagger: 0 # 1:enable 0:disable
   token-expire: 168h
   web-sso: true #web auth sso
-  disable-pwd-login: false #禁用密码登录
+  disable-pwd-login: false #disable password login
 
 admin:
   title: "RustDesk API Admin"
-  hello-file: "./conf/admin/hello.html"  #优先使用file
+  hello-file: "./conf/admin/hello.html"  #prefer to use a file for the welcome message
   hello: ""
   # ID Server and Relay Server ports https://github.com/lejianwen/rustdesk-api/issues/257
   id-server-port: 21116  # ID Server port (for server cmd)
@@ -20,7 +20,7 @@ admin:
 gin:
   api-addr: "0.0.0.0:21114"
   mode: "release" #release,debug,test
-  resources-path: 'resources'  #对外静态文件目录
+  resources-path: 'resources'  #public static file directory
   trust-proxy: ""
 gorm:
   type: "sqlite"