docs: Update Flash local testing docs with request format and docstring feature

flash/apps/local-testing.mdx

@@ -51,10 +51,26 @@ curl -X POST http://localhost:8888/lb_worker/process \
   -d '{"input_data": {"message": "Hello from Flash"}}'
 ```
 
+<Note>
+Queue-based endpoints require the `{"input": {...}}` wrapper to match the deployed endpoint behavior. The inner payload structure maps to your function's parameter names—the skeleton template uses `input_data: dict`, so the payload is `{"input_data": {...}}`. Load-balanced endpoints accept the payload directly without the `input` wrapper.
+</Note>
+
 ### Using the API explorer
 
 Open [http://localhost:8888/docs](http://localhost:8888/docs) in your browser to access the interactive Swagger UI. You can test all endpoints directly from the browser.
 
+Flash extracts the first line of each function's docstring and displays it as the endpoint description in the API explorer. Add docstrings to your `@Endpoint` functions to make your API self-documenting:
+
+```python
+@Endpoint(name="gpu-worker", gpu=GpuGroup.ANY)
+def process_data(input_data: dict) -> dict:
+    """Process input data and return computed results."""
+    # Function implementation
+    return {"result": "processed"}
+```
+
+The docstring "Process input data and return computed results" appears in the Swagger UI, making it easier to understand what each endpoint does.
+
 ### Using Python
 
 ```python

flash/cli/run.mdx

@@ -47,6 +47,25 @@ Enable or disable auto-reload on code changes. Enabled by default.
 Auto-provision all Serverless endpoints on startup instead of lazily on first call. Eliminates cold-start delays during development.
 </ResponseField>
 
+## Endpoint descriptions from docstrings
+
+Flash extracts the first line of each function's docstring and uses it in two places:
+
+- **Startup table**: The "Description" column shows the docstring when the server starts.
+- **Swagger UI**: The endpoint summary in the API explorer at `/docs`.
+
+Add docstrings to your `@Endpoint` functions to make your API self-documenting:
+
+```python
+@Endpoint(name="text-processor", gpu=GpuGroup.ANY)
+def analyze_text(text: str) -> dict:
+    """Analyze text and return sentiment scores."""
+    # Implementation here
+    return {"sentiment": "positive"}
+```
+
+When you run `flash run`, the startup table displays "Analyze text and return sentiment scores" as the description for this endpoint, and the same text appears in the Swagger UI summary.
+
 ## Architecture
 
 With `flash run`, Flash starts a local development server alongside remote Serverless endpoints:
@@ -144,6 +163,10 @@ curl -X POST http://localhost:8888/lb_worker/process \
   -d '{"input_data": {"message": "Hello from Flash"}}'
 ```
 
+<Note>
+Queue-based endpoints require the `{"input": {...}}` wrapper format to match deployed endpoint behavior. Load-balanced endpoints accept direct JSON payloads.
+</Note>
+
 Open http://localhost:8888/docs for the interactive API explorer.
 
 ## Requirements