refactor: update shell scripts for AI-Trader-Server rebrand

Update all shell scripts to use the new AI-Trader-Server naming throughout.

Changes:
- main.sh: Update comments and echo statements
- entrypoint.sh: Update startup message
- scripts/validate_docker_build.sh: Update title, container name references,
  and docker image tag from ai-trader-test to ai-trader-server-test
- scripts/test_api_endpoints.sh: Update title and docker-compose command

Part of Phase 4: Internal Configuration & Metadata (Task 19)

main.sh

@@ -1,11 +1,11 @@
 #!/bin/bash
 
-# AI-Trader 主启动脚本
+# AI-Trader-Server 主启动脚本
 # 用于启动完整的交易环境
 
 set -e  # 遇到错误时退出
 
-echo "🚀 Launching AI Trader Environment..."
+echo "🚀 Launching AI-Trader-Server Environment..."
 
 
 echo "📊 Now getting and merging price data..."
@@ -25,7 +25,7 @@ sleep 2
 echo "🤖 Now starting the main trading agent..."
 python main.py configs/default_config.json
 
-echo "✅ AI-Trader stopped"
+echo "✅ AI-Trader-Server stopped"
 
 echo "🔄 Starting web server..."
 cd ./docs