Fix ESLint fast-refresh warnings

Refactor to resolve react-refresh/only-export-components warnings:
- Move buttonVariants export to separate file (Button.variants.ts)
- Extract WebSocketContext to dedicated context file
- Move useWebSocketContext hook to separate file
- Update imports across affected files

All component files now export only components, improving fast refresh reliability

src/providers/useWebSocketContext.ts

@@ -0,0 +1,10 @@
+import { useContext } from 'react';
+import { WebSocketContext } from './WebSocketContext';
+
+export function useWebSocketContext() {
+  const context = useContext(WebSocketContext);
+  if (!context) {
+    throw new Error('useWebSocketContext must be used within a WebSocketProvider');
+  }
+  return context;
+}