feat(openai-ws): 合并 WS v2 透传模式与前端 ws mode

新增 OpenAI WebSocket v2 passthrough relay 数据面与服务适配层，
支持按账号 ws mode 在 ctx_pool 与 passthrough 间路由。

同步调整前端 OpenAI ws mode 选项为 off/ctx_pool/passthrough，
并补充 i18n 文案与对应单测。

新增 Caddyfile.dmit 与 docker-compose-aicodex.yml 部署配置，
用于宿主机场景下的反向代理与服务编排。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/i18n/locales/en.ts

@@ -1787,10 +1787,13 @@ export default {
         wsMode: 'WS mode',
         wsModeDesc: 'Only applies to the current OpenAI account type.',
         wsModeOff: 'Off (off)',
+        wsModeCtxPool: 'Context Pool (ctx_pool)',
+        wsModePassthrough: 'Passthrough (passthrough)',
         wsModeShared: 'Shared (shared)',
         wsModeDedicated: 'Dedicated (dedicated)',
         wsModeConcurrencyHint:
           'When WS mode is enabled, account concurrency becomes the WS connection pool limit for this account.',
+        wsModePassthroughHint: 'Passthrough mode does not use the WS connection pool.',
         oauthResponsesWebsocketsV2: 'OAuth WebSocket Mode',
         oauthResponsesWebsocketsV2Desc:
           'Only applies to OpenAI OAuth. This account can use OpenAI WebSocket Mode only when enabled.',

frontend/src/i18n/locales/zh.ts

@@ -1935,9 +1935,12 @@ export default {
         wsMode: 'WS mode',
         wsModeDesc: '仅对当前 OpenAI 账号类型生效。',
         wsModeOff: '关闭（off）',
+        wsModeCtxPool: '上下文池（ctx_pool）',
+        wsModePassthrough: '透传（passthrough）',
         wsModeShared: '共享（shared）',
         wsModeDedicated: '独享（dedicated）',
         wsModeConcurrencyHint: '启用 WS mode 后，该账号并发数将作为该账号 WS 连接池上限。',
+        wsModePassthroughHint: 'passthrough 模式不使用 WS 连接池。',
         oauthResponsesWebsocketsV2: 'OAuth WebSocket Mode',
         oauthResponsesWebsocketsV2Desc:
           '仅对 OpenAI OAuth 生效。开启后该账号才允许使用 OpenAI WebSocket Mode 协议。',