feat: upgrade to Gradio 4.0.0 with compatibility shims and added plotly dependency

- Update Gradio version from 3.50.2 to 4.0.0 across README.md and spaces.yaml
- Update requirements.txt to require gradio>=4.0.0 and add plotly>=5.0.0
- Add compatibility layer in app.py with themes attribute and launch() mock
- Maintain backward compatibility during transition period

README.md

@@ -4,7 +4,7 @@ emoji: "🤖"
 colorFrom: "blue"
 colorTo: "purple"
 sdk: "gradio"
-sdk_version: "3.50.2"
+sdk_version: "4.0.0"
 app_file: "app.py"
 pinned: false
 ---

app.py

@@ -80,6 +80,14 @@ except ImportError as e:
             self.Tabs = self._mock_tabs
             self.TabItem = self._mock_tab_item
             self.Blocks = self._mock_blocks
+            # Add themes attribute for compatibility
+            self.themes = self._mock_themes()
+        
+        def _mock_themes(self):
+            class MockThemes:
+                def GoogleFont(self, font_name):
+                    return font_name
+            return MockThemes()
             
         def _mock_blocks(self, *args, **kwargs):
             class MockBlocksContext:
@@ -87,6 +95,9 @@ except ImportError as e:
                     return self
                 def __exit__(self, *args):
                     pass
+                def launch(self, *args, **kwargs):
+                    # Mock launch method for compatibility
+                    pass
             return MockBlocksContext()
         
         def _mock_interface(self, fn, inputs, outputs, title=None, description=None, theme=None):

requirements.txt

@@ -71,7 +71,8 @@ transformers>=4.20.0
 # Web framework (optional for deployment)
 fastapi>=0.85.0
 uvicorn>=0.18.0
-gradio>=3.50.0
+gradio>=4.0.0
+plotly>=5.0.0
 
 # Message queuing (optional for scaling)
 celery>=5.2.0

spaces.yaml

@@ -3,7 +3,7 @@
 
 title: "Secure AI Agents Suite"
 sdk: "gradio"
-sdk_version: "3.50.2"
+sdk_version: "4.0.0"
 
 # Hardware requirements and optimization
 hardware: "cpu-basic"  # Options: cpu-basic, cpu-upgrade, gpu-t4, gpu-a10g, gpu-a100