feat: 初始化FastAPI项目基础框架

添加项目基础结构，包括：
- 核心模块(src/main.py)
- 路由模块(users/items)
- 数据库配置和模型
- 日志工具
- 测试用例
- 项目文档和依赖配置

.gitignore

@@ -0,0 +1,234 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak
+venv.bak
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Project specific
+test.db
+
+# Additions for better Python project management
+
+# Environment variables file
+.env.local
+.env.*.local
+
+# IDE and editor files
+.vscode/settings.json
+.vscode/tasks.json
+.vscode/launch.json
+.idea/
+*.sublime-project
+*.sublime-workspace
+
+# Operating System files
+.DS_Store*
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Icon?
+Thumbs.db
+
+# Logs
+*.log
+logs/
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Dependency directories
+node_modules/
+
+# Distribution / packaging
+.py[cod]
+*.so
+.Python
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+*.manifest
+*.spec
+
+# Coverage reports
+htmlcov/
+.coverage
+.coverage.*
+.cache
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# Database
+*.sqlite3
+*.db
+*.dump
+
+# Temporary files
+*.tmp
+*.temp
+~*
+*~
+
+# Compiled files
+*.com
+*.class
+*.dll
+*.exe
+*.o
+*.so
+
+# Packages
+*.7z
+*.dmg
+*.gz
+*.iso
+*.jar
+*.rar
+*.tar
+*.zip