feat: 新增支持codex转发

backend/internal/pkg/openai/request.go

@@ -0,0 +1,18 @@
+package openai
+
+// CodexCLIUserAgentPrefixes matches Codex CLI User-Agent patterns
+// Examples: "codex_vscode/1.0.0", "codex_cli_rs/0.1.2"
+var CodexCLIUserAgentPrefixes = []string{
+	"codex_vscode/",
+	"codex_cli_rs/",
+}
+
+// IsCodexCLIRequest checks if the User-Agent indicates a Codex CLI request
+func IsCodexCLIRequest(userAgent string) bool {
+	for _, prefix := range CodexCLIUserAgentPrefixes {
+		if len(userAgent) >= len(prefix) && userAgent[:len(prefix)] == prefix {
+			return true
+		}
+	}
+	return false
+}