feat(codex): pinned-accounts Codex model manifest for OpenAI groups

backend/internal/handler/openai_codex_models_handler.go

@@ -1,6 +1,7 @@
 package handler
 
 import (
+	"errors"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
@@ -50,6 +51,44 @@ func (h *OpenAIGatewayHandler) CodexModels(c *gin.Context) {
 		return
 	}
 
+	// 固定账号分支：开启后只用选定账号拉取 manifest，不经过调度器；
+	// 全部不可用/全部失败时按 FallbackToScheduler 决定回退调度器或返回错误。
+	if apiKey.Group.Platform == service.PlatformOpenAI &&
+		apiKey.Group.CodexModelsManifestConfig.Enabled &&
+		len(apiKey.Group.CodexModelsManifestConfig.AccountIDs) > 0 {
+		pinnedManifest, pinnedAccount, pinnedErr := h.gatewayService.FetchPinnedCodexModelsManifest(
+			c.Request.Context(),
+			apiKey.Group,
+			c.Query("client_version"),
+		)
+		if pinnedErr != nil {
+			if c.Request.Context().Err() != nil {
+				return
+			}
+			if !apiKey.Group.CodexModelsManifestConfig.FallbackToScheduler {
+				if errors.Is(pinnedErr, service.ErrNoPinnedCodexModelsAccounts) {
+					h.errorResponse(c, http.StatusServiceUnavailable, "upstream_error", "No available pinned OpenAI accounts")
+					return
+				}
+				h.errorResponse(c, infraerrors.Code(pinnedErr), "upstream_error", infraerrors.Message(pinnedErr))
+				return
+			}
+			// 回退开启：跌入下方调度器循环。
+		} else {
+			// 让 ops 错误日志携带实际拉取成功的首个固定账号。
+			setOpsSelectedAccount(c, pinnedAccount.ID, pinnedAccount.Platform)
+			if err := h.gatewayService.MergeGroupConfiguredCodexModels(c.Request.Context(), apiKey.Group, pinnedManifest, ifNoneMatch); err != nil {
+				h.errorResponse(c, http.StatusInternalServerError, "api_error", "Failed to build Codex models manifest")
+				return
+			}
+			if c.Request.Context().Err() != nil {
+				return
+			}
+			writeCodexModelsManifestResponse(c, pinnedManifest)
+			return
+		}
+	}
+
 	maxAccountSwitches := h.maxAccountSwitches
 	if maxAccountSwitches <= 0 {
 		maxAccountSwitches = 3