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.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+set -u
+
+SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
+REPO_ROOT="$(cd -- "$SCRIPT_DIR/.." && pwd -P)"
+PYTHON_EXE="${SYSTEM_SIMULATION_PYTHON:-$REPO_ROOT/.venv/bin/python}"
+
+if [[ "$PYTHON_EXE" != /* ]]; then
+  PYTHON_EXE="$REPO_ROOT/$PYTHON_EXE"
+fi
+
+if [[ ! -x "$PYTHON_EXE" ]]; then
+  echo "[ERROR] Python virtual environment was not found:" >&2
+  echo "        $PYTHON_EXE" >&2
+  echo >&2
+  echo "Create it and install the backend dependencies first:" >&2
+  echo "        python3 -m venv \"$REPO_ROOT/.venv\"" >&2
+  echo "        \"$REPO_ROOT/.venv/bin/python\" -m pip install -r \"$REPO_ROOT/requirements.txt\"" >&2
+  exit 1
+fi
+
+cd "$REPO_ROOT"
+
+echo "Starting FastAPI at http://127.0.0.1:8000"
+echo "Press Ctrl+C to stop the service."
+echo
+
+exec "$PYTHON_EXE" -m uvicorn app.main:app --host 127.0.0.1 --port 8000