feat: display user's heats in event chat header

- Show current user's heats in header next to connection status
- Display format: 'Your heats: J&J NOV 1 L, STR INT 2 L'
- Always visible - no need to click Edit Heats to see them
- Styled as badges matching sidebar heat badges

frontend/src/pages/EventChatPage.jsx

@@ -433,10 +433,27 @@ const EventChatPage = () => {
               <div className="flex-1">
                 <h2 className="text-2xl font-bold">{event.name}</h2>
                 <p className="text-primary-100 text-sm">{event.location}</p>
-                <div className="mt-2">
+                <div className="mt-2 flex items-center gap-3">
                   <span className={`text-xs px-2 py-1 rounded ${isConnected ? 'bg-green-500' : 'bg-red-500'}`}>
                     {isConnected ? '● Connected' : '● Disconnected'}
                   </span>
+
+                  {/* My Heats Display */}
+                  {myHeats.length > 0 && (
+                    <div className="flex items-center gap-2">
+                      <span className="text-xs text-primary-100">Your heats:</span>
+                      <div className="flex flex-wrap gap-1">
+                        {myHeats.map((heat, idx) => (
+                          <span
+                            key={idx}
+                            className="text-xs px-2 py-0.5 bg-primary-700 text-white rounded font-mono"
+                          >
+                            {formatHeat(heat)}
+                          </span>
+                        ))}
+                      </div>
+                    </div>
+                  )}
                 </div>
               </div>
               {myHeats.length > 0 && (