fix: replace complex bat scripts with Python launcher + minimal bat wrappers

Root cause: Windows batch files written with LF endings caused cmd.exe to
misparse labels and Chinese characters, producing garbled "not a command"
errors. The Python launcher avoids encoding issues entirely.

- start.py: reliable cross-platform launcher (kill ports, start 3 services,
  wait for health, print status)
- start.bat / start_all.bat: minimal 4-line ASCII wrappers
- stop.bat: inline Python for port-based process killing

start.bat

@@ -1,72 +1,4 @@
 @echo off
-chcp 65001 >nul
-setlocal enabledelayedexpansion
-echo ================================================
-echo   agent_jrxml 启动 (API + 验证)
-echo ================================================
 cd /d "%~dp0"
-
-:: ── 环境检查 ──
-if not exist "%~dp0.venv\Scripts\python.exe" (
-    echo [错误] 未找到 .venv，请先创建虚拟环境
-    pause
-    exit /b 1
-)
-
-echo.
-
-:: ── 清理残留进程 ──
-echo [清理] 检查残留进程...
-for /f "tokens=5" %%a in ('netstat -ano ^| findstr ":8000.*LISTENING"') do (
-    taskkill /F /PID %%a >nul 2>&1 && echo   已清理端口 8000 (PID %%a)
-)
-for /f "tokens=5" %%a in ('netstat -ano ^| findstr ":8001.*LISTENING"') do (
-    taskkill /F /PID %%a >nul 2>&1 && echo   已清理端口 8001 (PID %%a)
-)
-echo.
-
-:: ── 1. 验证服务 ──
-echo [启动] 验证服务 :8001
-start "jrxml-validator" .venv\Scripts\python.exe -c "import uvicorn; uvicorn.run('validation_service.main:app',host='0.0.0.0',port=8001,reload=False)" 2> "%~dp0logs\validator-stderr.log"
-
-echo [等待] 验证服务就绪...
-set /a N=0
-:wait_val
-ping -n 2 127.0.0.1 >nul
-powershell -Command "try{$r=Invoke-WebRequest -Uri http://localhost:8001/health -TimeoutSec 2 -UseBasicParsing;exit 0}catch{exit 1}" >nul 2>&1
-if not errorlevel 1 goto val_ok
-set /a N+=1
-if !N! GEQ 30 (
-    echo    [失败] 验证服务启动超时 (30次重试)
-    echo    请检查: logs\validator-stderr.log
-    goto cleanup
-)
-goto wait_val
-:val_ok
-echo    :8001 就绪
-
-:: ── 2. API 服务 (前台运行) ──
-echo [启动] API 服务 :8000
-echo ================================================
-echo   服务已就绪:
-echo     API:    http://localhost:8000/docs
-echo     验证:   http://localhost:8001/health
-echo   按 Ctrl+C 停止 API 服务
-echo   关闭窗口后会自动清理验证服务
-echo ================================================
-.venv\Scripts\python.exe -c "import uvicorn; uvicorn.run('api_server:app',host='0.0.0.0',port=8000,reload=False)"
-
-:: ── API 退出后清理 ──
-echo.
-echo [清理] 停止验证服务...
-taskkill /F /FI "WINDOWTITLE eq jrxml-validator*" >nul 2>&1
-for /f "tokens=5" %%a in ('netstat -ano ^| findstr ":8001.*LISTENING"') do taskkill /F /PID %%a >nul 2>&1
-echo 已停止所有服务
+.venv\Scripts\python.exe start.py
 pause
-exit /b 0
-
-:cleanup
-taskkill /F /FI "WINDOWTITLE eq jrxml-validator*" >nul 2>&1
-for /f "tokens=5" %%a in ('netstat -ano ^| findstr ":8001.*LISTENING"') do taskkill /F /PID %%a >nul 2>&1
-pause
-exit /b 1