feat: sap-cli skill v2.1.0 — self-contained distributable package

- assets/: sap-cli source (v2.1.0, 26 commands, 16 object types)
- references/: tool constraints + error handling (self-contained)
- scripts/setup.py: one-click install/config/verify
- SKILL.md: full command reference + dual-platform install guide
- VERSION: 2.1.0

Built from D:/Codespace/sap-cli via scripts/pack_skill.py

assets/requirements.txt

@@ -0,0 +1,9 @@
+# sap-cli 依赖
+# 本文件供不使用 pyproject.toml 的场景（如直接 pip install -r requirements.txt）使用。
+# 推荐使用 pip install -e . 或 pip install -e ".[dev]" 安装项目。
+#
+# 核心
+requests>=2.28.0
+
+# 可选：安全密码存储
+# keyring>=23.0