完成求解器雅可比矩阵首轮优化，增加更新目录，整理了文档文件夹，增加了服务启动脚本

bat/start-backend.bat

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+@echo off
+setlocal EnableExtensions DisableDelayedExpansion
+
+for %%I in ("%~dp0..") do set "REPO_ROOT=%%~fI"
+title SystemSimulationApp FastAPI - 127.0.0.1:8000
+
+set "PYTHON_EXE=%REPO_ROOT%\.venv-win\Scripts\python.exe"
+
+if not exist "%PYTHON_EXE%" (
+  echo [ERROR] Python virtual environment was not found:
+  echo         %PYTHON_EXE%
+  echo.
+  echo Create it and install the backend dependencies first:
+  echo         py -3 -m venv "%REPO_ROOT%\.venv-win"
+  echo         "%PYTHON_EXE%" -m pip install -r "%REPO_ROOT%\requirements.txt"
+  echo.
+  pause
+  exit /b 1
+)
+
+pushd "%REPO_ROOT%" >nul
+if errorlevel 1 (
+  echo [ERROR] Unable to enter the repository directory:
+  echo         %REPO_ROOT%
+  echo.
+  pause
+  exit /b 1
+)
+
+echo Starting FastAPI at http://127.0.0.1:8000
+echo Press Ctrl+C to stop the service.
+echo.
+
+"%PYTHON_EXE%" -m uvicorn app.main:app --host 127.0.0.1 --port 8000
+set "EXIT_CODE=%ERRORLEVEL%"
+
+if not "%EXIT_CODE%"=="0" (
+  echo.
+  echo [ERROR] FastAPI exited with code %EXIT_CODE%.
+  pause
+)
+
+popd
+exit /b %EXIT_CODE%