feat: add match slugs for security and fix message history loading

Security improvements:
- Add random CUID slugs to Match model to prevent ID enumeration attacks
- Update all match URLs from /matches/:id to /matches/:slug
- Keep numeric IDs for internal Socket.IO operations only

Backend changes:
- Add slug field to matches table with unique index
- Update all match endpoints to use slug-based lookups (GET, PUT, DELETE)
- Add GET /api/matches/:slug/messages endpoint to fetch message history
- Include matchSlug in all Socket.IO notifications

Frontend changes:
- Update all match routes to use slug parameter
- Update MatchesPage to use slug for accept/reject/navigate operations
- Update MatchChatPage to fetch match data by slug and load message history
- Update RatePartnerPage to use slug parameter
- Add matchesAPI.getMatchMessages() function

Bug fixes:
- Fix MatchChatPage not loading message history from database on mount
- Messages now persist and display correctly when users reconnect

frontend/src/pages/MatchesPage.jsx

@@ -66,13 +66,13 @@ const MatchesPage = () => {
 
   const handleMatchCancelled = (data) => {
     // Remove cancelled match from list
-    setMatches(prev => prev.filter(m => m.id !== data.matchId));
+    setMatches(prev => prev.filter(m => m.slug !== data.matchSlug));
   };
 
-  const handleAccept = async (matchId) => {
+  const handleAccept = async (matchSlug) => {
     try {
-      setProcessingMatchId(matchId);
-      await matchesAPI.acceptMatch(matchId);
+      setProcessingMatchId(matchSlug);
+      await matchesAPI.acceptMatch(matchSlug);
 
       // Reload matches
       await loadMatches();
@@ -87,17 +87,17 @@ const MatchesPage = () => {
     }
   };
 
-  const handleReject = async (matchId) => {
+  const handleReject = async (matchSlug) => {
     if (!confirm('Are you sure you want to reject this match request?')) {
       return;
     }
 
     try {
-      setProcessingMatchId(matchId);
-      await matchesAPI.deleteMatch(matchId);
+      setProcessingMatchId(matchSlug);
+      await matchesAPI.deleteMatch(matchSlug);
 
       // Remove from list
-      setMatches(prev => prev.filter(m => m.id !== matchId));
+      setMatches(prev => prev.filter(m => m.slug !== matchSlug));
     } catch (error) {
       console.error('Failed to reject match:', error);
       alert('Failed to reject match. Please try again.');
@@ -108,7 +108,7 @@ const MatchesPage = () => {
 
   const handleOpenChat = (match) => {
     if (match.status === 'accepted' && match.roomId) {
-      navigate(`/matches/${match.id}/chat`);
+      navigate(`/matches/${match.slug}/chat`);
     }
   };
 
@@ -187,7 +187,7 @@ const MatchesPage = () => {
                       onAccept={handleAccept}
                       onReject={handleReject}
                       onOpenChat={handleOpenChat}
-                      processing={processingMatchId === match.id}
+                      processing={processingMatchId === match.slug}
                     />
                   ))}
                 </div>
@@ -208,7 +208,7 @@ const MatchesPage = () => {
                       onAccept={handleAccept}
                       onReject={handleReject}
                       onOpenChat={handleOpenChat}
-                      processing={processingMatchId === match.id}
+                      processing={processingMatchId === match.slug}
                     />
                   ))}
                 </div>
@@ -295,7 +295,7 @@ const MatchCard = ({ match, onAccept, onReject, onOpenChat, processing }) => {
           {isIncoming && (
             <>
               <button
-                onClick={() => onAccept(match.id)}
+                onClick={() => onAccept(match.slug)}
                 disabled={processing}
                 className="p-2 bg-green-600 text-white rounded-full hover:bg-green-700 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
                 title="Accept"
@@ -307,7 +307,7 @@ const MatchCard = ({ match, onAccept, onReject, onOpenChat, processing }) => {
                 )}
               </button>
               <button
-                onClick={() => onReject(match.id)}
+                onClick={() => onReject(match.slug)}
                 disabled={processing}
                 className="p-2 bg-red-600 text-white rounded-full hover:bg-red-700 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
                 title="Reject"
@@ -319,7 +319,7 @@ const MatchCard = ({ match, onAccept, onReject, onOpenChat, processing }) => {
 
           {isOutgoing && (
             <button
-              onClick={() => onReject(match.id)}
+              onClick={() => onReject(match.slug)}
               disabled={processing}
               className="px-3 py-1.5 text-sm border border-gray-300 text-gray-700 rounded-md hover:bg-gray-50 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
             >