feat: leave-room button

- room:leave event: removes the player from the room (not just disconnected),
  reassigns host if the host leaves, deletes the room when empty
- store leaveRoom() emits it and clears the session (reset)
- room header gets a "Quitter" button (always available); end-screen "Quitter"
  now also leaves cleanly

Verified e2e: leaver removed from snapshot, host reassigned to the next player.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/server/src/handlers.ts

@@ -324,6 +324,22 @@ export function registerRoomHandlers(
     broadcastState(room)
   })
 
+  socket.on("room:leave", () => {
+    const code = socket.data.roomCode
+    const playerId = socket.data.playerId
+    if (!code || !playerId) {
+      return
+    }
+    socket.leave(code)
+    socket.data.roomCode = undefined
+    socket.data.playerId = undefined
+    const room = rooms.leave(code, playerId)
+    if (room) {
+      io.to(room.code).emit("player:left", { playerId })
+      broadcastState(room)
+    }
+  })
+
   socket.on("disconnect", () => {
     const affected = rooms.handleDisconnect(socket.id)
     if (!affected) {

apps/server/src/rooms.ts

@@ -94,6 +94,28 @@ export class RoomManager {
     return this.rooms.get(code)
   }
 
+  /**
+   * Retire un joueur d'une room (départ volontaire). Réassigne l'hôte si besoin,
+   * supprime la room si plus personne. Renvoie la room (ou null si supprimée).
+   */
+  leave(code: string, playerId: string): ServerRoom | null {
+    const room = this.rooms.get(code)
+    if (!room) {
+      return null
+    }
+    room.players.delete(playerId)
+    room.scores.delete(playerId)
+    if (room.players.size === 0) {
+      this.rooms.delete(code)
+      return null
+    }
+    if (room.hostId === playerId) {
+      const named = [...room.players.values()].find((p) => p.name !== "")
+      room.hostId = (named ?? [...room.players.values()][0]).id
+    }
+    return room
+  }
+
   /**
    * Marque le joueur d'un socket comme déconnecté.
    * Retourne la room affectée et le playerId, ou null si non rattaché.

apps/web/src/components/game-end-view.tsx

@@ -133,7 +133,7 @@ export function GameEndView({ snapshot }: { snapshot: RoomSnapshot }) {
   const finalScores = useRoomStore((s) => s.finalScores)
   const gameTracks = useRoomStore((s) => s.gameTracks)
   const gameRecap = useRoomStore((s) => s.gameRecap)
-  const reset = useRoomStore((s) => s.reset)
+  const leaveRoom = useRoomStore((s) => s.leaveRoom)
   const returnToLobby = useRoomStore((s) => s.returnToLobby)
   const isHost = snapshot.hostId === playerId
 
@@ -284,7 +284,7 @@ export function GameEndView({ snapshot }: { snapshot: RoomSnapshot }) {
           </p>
         )}
         <Link href="/">
-          <Button variant="secondary" className="w-full" onClick={reset}>
+          <Button variant="secondary" className="w-full" onClick={leaveRoom}>
             Quitter
           </Button>
         </Link>

apps/web/src/pages/room.tsx

@@ -1,5 +1,6 @@
-import { Link } from "wouter"
+import { Link, useLocation } from "wouter"
 import { AnimatePresence, motion } from "framer-motion"
+import { LogOut } from "lucide-react"
 import { Button } from "@workspace/ui/components/button"
 import { useRoomStore } from "@/store/room"
 import { LobbyView } from "@/components/lobby-view"
@@ -13,8 +14,10 @@ import { RoundTransition } from "@/components/round-transition"
 import { PseudoScreen } from "@/components/pseudo-screen"
 
 export function RoomPage({ code }: { code: string }) {
+  const [, navigate] = useLocation()
   const snapshot = useRoomStore((s) => s.snapshot)
   const roomCode = useRoomStore((s) => s.roomCode)
+  const leaveRoom = useRoomStore((s) => s.leaveRoom)
   const playerId = useRoomStore((s) => s.playerId)
   const connected = useRoomStore((s) => s.connected)
   const pseudoSet = useRoomStore((s) => s.pseudoSet)
@@ -80,10 +83,22 @@ export function RoomPage({ code }: { code: string }) {
       >
         <header className="flex items-center justify-between">
           <RoomCode code={snapshot.code} />
+          <div className="flex items-center gap-3">
             <span
               className={`size-2.5 rounded-full ${connected ? "bg-green-500" : "bg-red-500"}`}
               title={connected ? "Connecté" : "Déconnecté"}
             />
+            <Button
+              size="sm"
+              variant="secondary"
+              onClick={() => {
+                leaveRoom()
+                navigate("/")
+              }}
+            >
+              <LogOut /> Quitter
+            </Button>
+          </div>
         </header>
 
         <AnimatePresence mode="wait">

apps/web/src/store/room.ts

@@ -77,6 +77,7 @@ interface RoomState {
   submitTrack: (youtubeUrl: string) => Promise<SubmitOkPayload>
   removeTrack: (trackId: string) => Promise<boolean>
   returnToLobby: () => void
+  leaveRoom: () => void
   vote: (choiceIndex: number) => void
   voteText: (text: string) => void
   voteBlindtest: (answer: BlindtestAnswer) => void
@@ -192,6 +193,11 @@ export const useRoomStore = create<RoomState>((set, get) => ({
     socket.emit("lobby:return")
   },
 
+  leaveRoom: () => {
+    socket.emit("room:leave")
+    get().reset()
+  },
+
   vote: (choiceIndex) => {
     if (get().hasVoted) {
       return

packages/shared/src/events.ts

@@ -149,6 +149,7 @@ export interface ClientToServerEvents {
   "room:join": (payload: RoomJoinPayload, ack: Ack<RoomCreatedPayload>) => void
   "room:rejoin": (payload: RejoinPayload, ack: Ack<RoomCreatedPayload>) => void
   "player:setName": (payload: SetNamePayload) => void
+  "room:leave": () => void
   "lobby:updateSettings": (payload: UpdateSettingsPayload) => void
   "lobby:return": () => void
   "game:start": (ack: Ack<null>) => void