Go: unify three services into one binary (#16462)

### Summary

Plan to start api_server, admin_server and ingestor in one binary:
- ./ragflow_main --admin
- ./ragflow_main --api
- ./ragflow_main --ingestor

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/server/config.go

@@ -905,11 +905,11 @@ func PrintAll() {
 	}
 
 	allSettings := globalViper.AllSettings()
-	zapLogger.Info("=== All Configuration Settings ===")
+	zapLogger.Info("=== All Configurations ===")
 	for key, value := range allSettings {
 		zapLogger.Info("config", zap.String("key", key), zap.Any("value", value))
 	}
-	zapLogger.Info("=== End Configuration ===")
+	zapLogger.Info("=== End Configurations ===")
 }
 
 // parseHostPort parses host:port string and returns host and port

internal/server/local_variables.go

@@ -0,0 +1,53 @@
+//
+//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+package server
+
+import (
+	"ragflow/internal/common"
+	"sync"
+)
+
+type LocalVariables struct {
+	ServerName *string // Server name, can be modified at runtime
+}
+
+var (
+	localVariables     *LocalVariables
+	localVariablesOnce sync.Once
+	localVariablesMu   sync.RWMutex
+)
+
+func InitLocalVariables() error {
+	var initErr error
+	localVariablesOnce.Do(func() {
+		localVariables = &LocalVariables{}
+		common.Info("Local variables initialized successfully")
+	})
+	return initErr
+}
+
+func SetServerName(serverName string) {
+	localVariablesMu.Lock()
+	defer localVariablesMu.Unlock()
+	localVariables.ServerName = &serverName
+}
+
+func GetServerName() string {
+	localVariablesMu.RLock()
+	defer localVariablesMu.RUnlock()
+	return *localVariables.ServerName
+}