feat(openai): 支持messages模型映射与instructions模板注入

backend/internal/config/config_test.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -223,6 +225,23 @@ func TestLoadSchedulingConfigFromEnv(t *testing.T) {
 	}
 }
 
+func TestLoadForcedCodexInstructionsTemplate(t *testing.T) {
+	resetViperWithJWTSecret(t)
+
+	tempDir := t.TempDir()
+	templatePath := filepath.Join(tempDir, "codex-instructions.md.tmpl")
+	configPath := filepath.Join(tempDir, "config.yaml")
+
+	require.NoError(t, os.WriteFile(templatePath, []byte("server-prefix\n\n{{ .ExistingInstructions }}"), 0o644))
+	require.NoError(t, os.WriteFile(configPath, []byte("gateway:\n  forced_codex_instructions_template_file: \""+templatePath+"\"\n"), 0o644))
+	t.Setenv("DATA_DIR", tempDir)
+
+	cfg, err := Load()
+	require.NoError(t, err)
+	require.Equal(t, templatePath, cfg.Gateway.ForcedCodexInstructionsTemplateFile)
+	require.Equal(t, "server-prefix\n\n{{ .ExistingInstructions }}", cfg.Gateway.ForcedCodexInstructionsTemplate)
+}
+
 func TestLoadDefaultSecurityToggles(t *testing.T) {
 	resetViperWithJWTSecret(t)