chore: Perform codebase cleanup and refactor App state management

backend/src/ea_chatbot/utils/plots.py

@@ -0,0 +1,17 @@
+import io
+import matplotlib.pyplot as plt
+
+def fig_to_bytes(fig: plt.Figure, format: str = "png") -> bytes:
+    """
+    Convert a Matplotlib figure to bytes.
+    
+    Args:
+        fig: The Matplotlib figure to convert.
+        format: The image format to use (default: "png").
+        
+    Returns:
+        bytes: The image data.
+    """
+    buf = io.BytesIO()
+    fig.savefig(buf, format=format)
+    return buf.getvalue()