feat: add one-click startup scripts for project management

- Add start.sh/start.bat for one-click startup (backend + frontend)
- Add stop.sh/stop.bat for stopping all services
- Add restart.sh for restarting services
- Add status.sh for checking service status
- Add Makefile with convenient management commands
- Add comprehensive documentation (ONE_CLICK_START.md)
- Update README with one-click startup instructions

Features:
- Automatic environment checking (venv, node_modules)
- Process management with PID tracking
- Unified log management (logs/*.log)
- Health checking after startup
- Support for Linux, macOS, and Windows
- No more need for multiple terminal windows

Usage:
  ./start.sh      # Start all services
  ./stop.sh       # Stop all services
  ./status.sh     # Check service status
  ./restart.sh    # Restart services
  make start      # Alternative using Makefile

Benefits:
- One command instead of multiple terminals
- Automatic environment validation
- Centralized logging
- Process lifecycle management
- Developer-friendly output messages

stop.sh

@@ -0,0 +1,69 @@
+#!/bin/bash
+# ERP AI Assistant - 停止脚本
+
+set -e
+
+# 颜色定义
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+# 项目根目录
+PROJECT_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PID_FILE="$PROJECT_ROOT/logs/pids.txt"
+
+echo -e "${BLUE}========================================${NC}"
+echo -e "${BLUE}   ERP AI Assistant - 停止中...${NC}"
+echo -e "${BLUE}========================================${NC}"
+echo ""
+
+if [ ! -f "$PID_FILE" ]; then
+    echo -e "${YELLOW}⚠ 未找到 PID 文件，服务可能未运行${NC}"
+    exit 0
+fi
+
+# 读取并停止进程
+STOPPED=0
+FAILED=0
+
+while read pid; do
+    if kill -0 "$pid" 2>/dev/null; then
+        PROCESS_NAME=$(ps -p "$pid" -o comm= 2>/dev/null || echo "Unknown")
+        echo -e "${YELLOW}停止进程: $pid ($PROCESS_NAME)${NC}"
+        if kill "$pid" 2>/dev/null; then
+            echo -e "${GREEN}✓ 进程 $pid 已停止${NC}"
+            ((STOPPED++))
+        else
+            echo -e "${RED}✗ 无法停止进程 $pid${NC}"
+            ((FAILED++))
+        fi
+    else
+        echo -e "${YELLOW}  进程 $pid 已不存在${NC}"
+    fi
+done < "$PID_FILE"
+
+# 等待进程完全停止
+sleep 2
+
+# 强制杀死残留进程
+while read pid; do
+    if kill -0 "$pid" 2>/dev/null; then
+        echo -e "${YELLOW}强制停止进程: $pid${NC}"
+        kill -9 "$pid" 2>/dev/null || true
+    fi
+done < "$PID_FILE"
+
+# 清理 PID 文件
+rm -f "$PID_FILE"
+
+echo ""
+echo -e "${GREEN}========================================${NC}"
+echo -e "${GREEN}   ✅ 停止完成${NC}"
+echo -e "${GREEN}========================================${NC}"
+echo -e "   已停止: $STOPPED 个进程"
+if [ $FAILED -gt 0 ]; then
+    echo -e "   失败: ${RED}$FAILED${NC} 个进程"
+fi
+echo ""