feat(channel-monitor): 补充协议选择文案

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/i18n/locales/en.ts

@@ -2622,6 +2622,11 @@ export default {
         name: 'Name',
         namePlaceholder: 'Enter monitor name',
         provider: 'Platform',
+        apiMode: 'OpenAI protocol',
+        apiModeChatCompletions: 'OpenAI Compatible',
+        apiModeChatCompletionsHint: 'Use /v1/chat/completions with messages; works for most compatible providers.',
+        apiModeResponses: 'Responses API',
+        apiModeResponsesHint: 'Use /v1/responses with default instructions + input; best for self-check/Codex paths.',
         endpoint: 'Endpoint',
         endpointPlaceholder: 'https://api.example.com',
         useCurrentDomain: 'Use current service',

frontend/src/i18n/locales/zh.ts

@@ -2699,6 +2699,11 @@ export default {
         name: '名称',
         namePlaceholder: '输入监控名称',
         provider: '平台',
+        apiMode: 'OpenAI 协议',
+        apiModeChatCompletions: 'OpenAI Compatible',
+        apiModeChatCompletionsHint: '使用 /v1/chat/completions，发送 messages；适合大多数兼容站。',
+        apiModeResponses: 'Responses API',
+        apiModeResponsesHint: '使用 /v1/responses，默认带 instructions + input；适合本站自检/Codex。',
         endpoint: '上游地址',
         endpointPlaceholder: 'https://api.example.com',
         useCurrentDomain: '使用当前服务',