feat(events): add competitor number (bib) support

Allow participants to set their bib/competitor number per event.
Display as badge next to username in participant lists.

- Add competitorNumber field to EventParticipant model
- Add PUT /events/:slug/competitor-number endpoint
- Include competitorNumber in heats/me and heats/all responses
- Add input field in HeatsBanner component
- Display badge in UserListItem component
- Add unit tests for competitor number feature

frontend/src/pages/EventChatPage.jsx

@@ -43,7 +43,9 @@ const EventChatPage = () => {
 
   // Heats state
   const [myHeats, setMyHeats] = useState([]);
+  const [myCompetitorNumber, setMyCompetitorNumber] = useState(null);
   const [userHeats, setUserHeats] = useState(new Map());
+  const [userCompetitorNumbers, setUserCompetitorNumbers] = useState(new Map());
   const [showHeatsBanner, setShowHeatsBanner] = useState(false);
   const [hideMyHeats, setHideMyHeats] = useState(false);
   const [showHeatsModal, setShowHeatsModal] = useState(false);
@@ -87,18 +89,25 @@ const EventChatPage = () => {
 
     const loadData = async () => {
       try {
-        // Load my heats
-        const myHeatsData = await heatsAPI.getMyHeats(slug);
+        // Load my heats and competitor number
+        const myHeatsResponse = await heatsAPI.getMyHeats(slug);
+        const myHeatsData = myHeatsResponse.data || [];
         setMyHeats(myHeatsData);
+        setMyCompetitorNumber(myHeatsResponse.competitorNumber);
         setShowHeatsBanner(myHeatsData.length === 0);
 
-        // Load all users' heats
+        // Load all users' heats and competitor numbers
         const allHeatsData = await heatsAPI.getAllHeats(slug);
         const heatsMap = new Map();
+        const competitorNumbersMap = new Map();
         allHeatsData.forEach((userHeat) => {
           heatsMap.set(userHeat.userId, userHeat.heats);
+          if (userHeat.competitorNumber) {
+            competitorNumbersMap.set(userHeat.userId, userHeat.competitorNumber);
+          }
         });
         setUserHeats(heatsMap);
+        setUserCompetitorNumbers(competitorNumbersMap);
 
         // Load all checked-in users (participants)
         const eventDetails = await eventsAPI.getDetails(slug);
@@ -384,6 +393,7 @@ const EventChatPage = () => {
               slug={slug}
               onSave={handleHeatsSave}
               onDismiss={() => setShowHeatsBanner(false)}
+              existingCompetitorNumber={myCompetitorNumber}
             />
           )}
 
@@ -392,6 +402,7 @@ const EventChatPage = () => {
               users={getAllDisplayUsers().filter(u => !shouldHideUser(u.userId))}
               activeUsers={activeUsers}
               userHeats={userHeats}
+              userCompetitorNumbers={userCompetitorNumbers}
               myHeats={myHeats}
               hideMyHeats={hideMyHeats}
               onHideMyHeatsChange={setHideMyHeats}
@@ -457,6 +468,7 @@ const EventChatPage = () => {
             onSave={handleHeatsSave}
             onDismiss={() => setShowHeatsModal(false)}
             existingHeats={myHeats}
+            existingCompetitorNumber={myCompetitorNumber}
           />
         </Modal>
       </div>