feat: add time controls, correspondence games, and tournament mode

**Zeitmodi (Blitz/Rapid):**
- 5, 10, 30 Min Zeitkontrolle bei Spielerstellung
- Server-seitige Uhren: Zeit wird bei jedem Zug abgezogen
- Timeout-Erkennung via claimTimeout Socket-Event
- Schachuhr-Anzeige in GamePage (rot bei < 30s)
- Turnierspiele erhalten automatisch Zeitkontrolle

**Tagespartien (Correspondence):**
- Neue DB-Tabelle correspondence_game
- REST API: erstellen, beitreten, Zug machen, aufgeben
- Seite /correspondence: Liste aktiver Tagespartien
- Seite /correspondence/[code]: Spielen mit interaktivem Brett
- Einladungslink teilen, Gegner tritt via Link bei

**Turniermodus (Round-Robin):**
- Neue DB-Tabellen: tournament, tournament_player, tournament_round
- Round-Robin Paarungen mit Circle-Methode
- Turnier erstellen: /tournament/create
- Turnierliste: /tournament
- Turnierseite /tournament/[code]: Standings, Runden, Spiele
- Automatische Aktivisierung der nächsten Runde
- Turnierspiele werden als normale activeGames erstellt
- Ergebnisse aktualisieren Punkte automatisch

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/components/game/GamePage.tsx

@@ -54,6 +54,11 @@ export default function GamePage({ initialLobby }: { initialLobby: Game }) {
   const [navFen, setNavFen] = useState<string | null>(null);
   const [navIndex, setNavIndex] = useState<number | null>(null);
 
+  const [clockWhite, setClockWhite] = useState<number | null>(null);
+  const [clockBlack, setClockBlack] = useState<number | null>(null);
+  const clockRef = useRef<{ whiteTimeMs: number; blackTimeMs: number; clientLastMoveAt: number } | null>(null);
+  const lobbyRef = useRef(lobby);
+
   const [playBtnLoading, setPlayBtnLoading] = useState(false);
   const [copiedLink, setCopiedLink] = useState(false);
   const [chatMessages, setChatMessages] = useState<Message[]>([
@@ -65,6 +70,30 @@ export default function GamePage({ initialLobby }: { initialLobby: Game }) {
   const chatListRef = useRef<HTMLUListElement>(null);
   const moveListRef = useRef<HTMLDivElement>(null);
 
+  // Keep lobbyRef in sync so clock interval can read latest lobby without re-registering
+  useEffect(() => { lobbyRef.current = lobby; }, [lobby]);
+
+  // Clock interval — only active when timeControl is set
+  useEffect(() => {
+    if (!initialLobby.timeControl) return;
+    const interval = setInterval(() => {
+      if (!clockRef.current) return;
+      const l = lobbyRef.current;
+      if (l.endReason || l.winner) return;
+      const elapsed = Date.now() - clockRef.current.clientLastMoveAt;
+      const turn = l.actualGame.turn();
+      const white = turn === "w" ? Math.max(0, clockRef.current.whiteTimeMs - elapsed) : clockRef.current.whiteTimeMs;
+      const black = turn === "b" ? Math.max(0, clockRef.current.blackTimeMs - elapsed) : clockRef.current.blackTimeMs;
+      setClockWhite(white);
+      setClockBlack(black);
+      if ((turn === "w" && white <= 0) || (turn === "b" && black <= 0)) {
+        socket.emit("claimTimeout");
+      }
+    }, 100);
+    return () => clearInterval(interval);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [initialLobby.timeControl]);
+
   const [abandonSeconds, setAbandonSeconds] = useState(60);
   useEffect(() => {
     if (
@@ -114,7 +143,14 @@ export default function GamePage({ initialLobby }: { initialLobby: Game }) {
       updateCustomSquares,
       makeMove,
       setNavFen,
-      setNavIndex
+      setNavIndex,
+      onClockUpdate: ({ whiteTimeMs, blackTimeMs, lastMoveAt }) => {
+        clockRef.current = { whiteTimeMs, blackTimeMs, clientLastMoveAt: Date.now() };
+        setClockWhite(whiteTimeMs);
+        setClockBlack(blackTimeMs);
+        // suppress unused-warning on lastMoveAt — stored via clientLastMoveAt above
+        void lastMoveAt;
+      }
     });
 
     return () => {
@@ -503,6 +539,12 @@ export default function GamePage({ initialLobby }: { initialLobby: Game }) {
     };
   }
 
+  function formatClock(ms: number | null): string {
+    if (ms === null) return "--:--";
+    const s = Math.max(0, Math.ceil(ms / 1000));
+    return `${Math.floor(s / 60)}:${String(s % 60).padStart(2, "0")}`;
+  }
+
   function claimAbandoned(type: "win" | "draw") {
     if (
       lobby.side === "s" ||
@@ -568,6 +610,29 @@ export default function GamePage({ initialLobby }: { initialLobby: Game }) {
             {getPlayerHtml("bottom")}
           </div>
 
+          {initialLobby.timeControl && (
+            <div className="flex flex-col items-end justify-between gap-1 pl-2">
+              {/* Top clock = opponent */}
+              <div className={
+                "font-mono text-lg font-bold px-2 py-1 rounded " +
+                (lobby.side === "b"
+                  ? (clockWhite !== null && clockWhite < 30000 ? "bg-error text-error-content" : "bg-base-300")
+                  : (clockBlack !== null && clockBlack < 30000 ? "bg-error text-error-content" : "bg-base-300"))
+              }>
+                {lobby.side === "b" ? formatClock(clockWhite) : formatClock(clockBlack)}
+              </div>
+              {/* Bottom clock = self */}
+              <div className={
+                "font-mono text-lg font-bold px-2 py-1 rounded " +
+                (lobby.side === "b"
+                  ? (clockBlack !== null && clockBlack < 30000 ? "bg-error text-error-content" : "bg-base-300")
+                  : (clockWhite !== null && clockWhite < 30000 ? "bg-error text-error-content" : "bg-base-300"))
+              }>
+                {lobby.side === "b" ? formatClock(clockBlack) : formatClock(clockWhite)}
+              </div>
+            </div>
+          )}
+
           <div className="flex flex-1 flex-col gap-1">
             <div className="mb-2 flex w-full flex-col items-end gap-1">
               {lobby.endReason ? "Archived link:" : "Invite friends:"}