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>

fastgpt_client/__init__.py

@@ -0,0 +1,30 @@
+"""FastGPT Python SDK
+
+A Python client library for interacting with FastGPT's OpenAPI.
+"""
+
+from fastgpt_client.client import AppClient, ChatClient, FastGPTClient
+from fastgpt_client.exceptions import (
+    APIError,
+    AuthenticationError,
+    FastGPTError,
+    RateLimitError,
+    StreamParseError,
+    ValidationError,
+)
+
+__all__ = [
+    # Synchronous clients
+    "FastGPTClient",
+    "ChatClient",
+    "AppClient",
+    # Exceptions
+    "FastGPTError",
+    "APIError",
+    "AuthenticationError",
+    "RateLimitError",
+    "ValidationError",
+    "StreamParseError",
+]
+
+__version__ = "0.1.0"