feat: add chat_tui example for FastGPT with Textual interface

- Introduced a new example script `chat_tui.py` that provides a full-screen Textual interface for interacting with FastGPT.
- Implemented streaming chat updates, workflow logging, and modal handling for interactive nodes.
- Enhanced FastGPT client with new streaming capabilities and structured event types for better interaction handling.
- Normalized base URL handling in the client to prevent duplicate `/api` paths.
- Added tests for streaming event parsing and interaction handling.

fastgpt_client/__init__.py

@@ -1,4 +1,4 @@
-"""FastGPT Python SDK
+"""FastGPT Python SDK
 
 A Python client library for interacting with FastGPT's OpenAPI.
 """
@@ -17,6 +17,8 @@ from fastgpt_client.exceptions import (
     StreamParseError,
     ValidationError,
 )
+from fastgpt_client.streaming import aiter_stream_events, iter_stream_events
+from fastgpt_client.stream_types import FastGPTInteractiveEvent, FastGPTStreamEvent
 
 __all__ = [
     # Synchronous clients
@@ -34,6 +36,11 @@ __all__ = [
     "RateLimitError",
     "ValidationError",
     "StreamParseError",
+    # Streaming helpers
+    "iter_stream_events",
+    "aiter_stream_events",
+    "FastGPTStreamEvent",
+    "FastGPTInteractiveEvent",
 ]
 
 __version__ = "0.1.0"