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/client.py

@@ -43,9 +43,10 @@ class FastGPTClient(BaseClientMixin):
         # Initialize base client functionality
         super().__init__(api_key, base_url, timeout, max_retries, retry_delay, enable_logging)
 
+        connect_timeout = min(float(timeout), 15.0) if timeout and timeout > 0 else 15.0
         self._client = httpx.Client(
-            base_url=base_url,
-            timeout=httpx.Timeout(timeout, connect=5.0),
+            base_url=self.base_url,
+            timeout=httpx.Timeout(timeout, connect=connect_timeout),
         )
 
     def __enter__(self):
@@ -206,6 +207,19 @@ class FastGPTClient(BaseClientMixin):
         try:
             error_data = response.json()
             message = error_data.get("message", f"HTTP {response.status_code}")
+        except httpx.ResponseNotRead:
+            try:
+                response.read()
+                error_data = response.json()
+                message = error_data.get("message", f"HTTP {response.status_code}")
+            except Exception:
+                error_text = ""
+                try:
+                    error_text = response.text.strip()
+                except Exception:
+                    error_text = ""
+                message = error_text or f"HTTP {response.status_code}"
+                error_data = None
         except (ValueError, KeyError, AttributeError):
             # If we can't parse JSON (e.g., streaming response or invalid JSON), use status code
             message = f"HTTP {response.status_code}"