Initial commit: FastGPT Python SDK Phase 1

Implement core infrastructure:

- BaseClientMixin with retry logic and validation
- FastGPTClient base class with httpx
- ChatClient with 11 chat operation methods
- AppClient for analytics and logs
- Custom exceptions (APIError, AuthenticationError, etc.)
- Package configuration (pyproject.toml, setup.py)
- Documentation (README.md, CLAUDE.md)
- Basic usage examples

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,59 @@
+[build-system]
+requires = ["setuptools>=68.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "fastgpt-client"
+version = "0.1.0"
+description = "Python SDK for FastGPT OpenAPI"
+readme = "README.md"
+requires-python = ">=3.8"
+license = {text = "MIT"}
+authors = [
+    {name = "Your Name", email = "your.email@example.com"}
+]
+keywords = ["fastgpt", "ai", "chatbot", "llm", "openapi"]
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+]
+dependencies = [
+    "httpx>=0.25.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=7.0",
+    "pytest-cov>=4.0",
+    "ruff>=0.1.0",
+]
+
+[project.urls]
+Homepage = "https://github.com/yourusername/fastgpt-python-sdk"
+Documentation = "https://github.com/yourusername/fastgpt-python-sdk#readme"
+Repository = "https://github.com/yourusername/fastgpt-python-sdk"
+Issues = "https://github.com/yourusername/fastgpt-python-sdk/issues"
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["fastgpt_client*"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py38"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "N", "W"]
+ignore = ["E501"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+python_files = ["test_*.py"]