feat(display): countdown, fallback su immagine e dissolvenza nell'overlay time out

L'overlay ora riproduce il video scelto dal controller mostrando un
countdown 00:30→00:00 calcolato dallo stato condiviso. Se il video finisce
prima dei 30s subentra un'immagine "TIME OUT + nome squadra" fino allo
scadere; se dura più di 30s si applica una dissolvenza CSS negli ultimi
istanti. In caso di riconnessione a metà time out il video viene
riallineato (currentTime) al punto corretto.

src/components/DisplayPage.vue

@@ -113,10 +113,14 @@
       </div>
     </div>
 
-    <!-- Overlay time out: proietta i video spot a tutto schermo -->
+    <!-- Overlay time out: proietta il video spot a tutto schermo -->
     <div v-if="state.timeout" class="timeout-overlay">
-      <video v-if="spotList.length" ref="spotVideo" class="timeout-video" playsinline></video>
-      <div v-else class="timeout-placeholder">TIME OUT</div>
+      <div class="timeout-countdown">{{ timeoutCountdown }}</div>
+      <video v-if="state.timeoutVideo && !mostraPlaceholder" ref="spotVideo" class="timeout-video"
+        :class="{ 'timeout-video--fading': timeoutFading }" playsinline></video>
+      <div v-else class="timeout-placeholder">
+        TIME OUT<br />{{ state.sp.nomi[state.timeoutTeam] }}
+      </div>
     </div>
   </section>
 </template>
@@ -129,16 +133,38 @@ export default {
   mixins: [createWsMixin('display')],
   data() {
     return {
-      spotList: [],   // filename dei video spot da riprodurre
-      spotIndex: 0,   // video corrente nella sequenza
+      mostraPlaceholder: false, // video terminato prima dei 30s: mostra l'immagine "TIME OUT"
+      spotVideoDuration: null,  // durata reale del video in riproduzione, nota dopo il loadedmetadata
+      nowTick: Date.now(),
+      timeoutTicker: null,
     }
   },
   mounted() {
     if (this.isMobile()) {
       try { document.documentElement.requestFullscreen() } catch (e) {}
     }
+    if (this.state.timeout) this.avviaTimeout()
+  },
+  beforeUnmount() {
+    this.fermaTimeoutTicker()
   },
   computed: {
+    timeoutRemaining() {
+      if (!this.state.timeout || !this.state.timeoutStartedAt) return 30
+      const trascorsi = (this.nowTick - this.state.timeoutStartedAt) / 1000
+      return Math.max(0, Math.ceil(30 - trascorsi))
+    },
+    timeoutCountdown() {
+      const r = this.timeoutRemaining
+      const m = String(Math.floor(r / 60)).padStart(2, '0')
+      const s = String(r % 60).padStart(2, '0')
+      return `${m}:${s}`
+    },
+    timeoutFading() {
+      // Video più lungo di 30s: dissolvenza negli ultimi istanti prima dello stop del server.
+      if (!this.spotVideoDuration || this.spotVideoDuration <= 30) return false
+      return this.timeoutRemaining <= 1
+    },
     stricciaStrip() {
       const currentSet = this.state.sp.striscia.at(-1)
       if (!currentSet) return { home: [], guest: [] }
@@ -168,32 +194,41 @@ export default {
     },
   },
   methods: {
+    avviaTimeoutTicker() {
+      this.fermaTimeoutTicker()
+      this.nowTick = Date.now()
+      this.timeoutTicker = setInterval(() => { this.nowTick = Date.now() }, 200)
+    },
+    fermaTimeoutTicker() {
+      if (this.timeoutTicker) { clearInterval(this.timeoutTicker); this.timeoutTicker = null }
+    },
     async avviaTimeout() {
-      this.spotIndex = 0
-      try {
-        const res = await fetch('/spot/list')
-        this.spotList = await res.json()
-      } catch {
-        this.spotList = []
-      }
-      if (!this.spotList.length) return
+      this.mostraPlaceholder = !this.state.timeoutVideo
+      this.spotVideoDuration = null
+      this.avviaTimeoutTicker()
+      if (!this.state.timeoutVideo) return
       await this.$nextTick()
       this.caricaSpotCorrente()
     },
     fermaTimeout() {
+      this.fermaTimeoutTicker()
       const video = this.$refs.spotVideo
       if (video) { video.pause(); video.removeAttribute('src'); video.load() }
-      this.spotList = []
+      this.mostraPlaceholder = false
+      this.spotVideoDuration = null
     },
     caricaSpotCorrente() {
       const video = this.$refs.spotVideo
-      if (!video || !this.spotList.length) return
-      video.src = '/spot/' + encodeURIComponent(this.spotList[this.spotIndex])
-      // Avanza al prossimo video alla fine (loop: con un solo video torna su sé stesso)
-      video.onended = () => {
-        this.spotIndex = (this.spotIndex + 1) % this.spotList.length
-        this.caricaSpotCorrente()
+      if (!video || !this.state.timeoutVideo) return
+      video.src = '/spot/' + encodeURIComponent(this.state.timeoutVideo)
+      video.onloadedmetadata = () => {
+        this.spotVideoDuration = video.duration
+        // Riconnessione a metà time out: riallinea il video al punto corretto.
+        const trascorsi = this.state.timeoutStartedAt ? (Date.now() - this.state.timeoutStartedAt) / 1000 : 0
+        if (trascorsi > 0.5 && trascorsi < video.duration) video.currentTime = trascorsi
       }
+      // Video più corto dei 30s: a fine riproduzione mostra l'immagine "TIME OUT" fino allo stop del server.
+      video.onended = () => { this.mostraPlaceholder = true }
       this.playSpot()
     },
     playSpot() {
@@ -320,14 +355,37 @@ export default {
   width: 100%;
   height: 100%;
   object-fit: contain;
+  transition: opacity 0.8s ease-out;
+}
+
+.timeout-video--fading {
+  opacity: 0;
+}
+
+.timeout-countdown {
+  position: absolute;
+  top: 24px;
+  left: 50%;
+  transform: translateX(-50%);
+  color: #fff;
+  background: rgba(0, 0, 0, 0.5);
+  font-size: 4vh;
+  font-weight: 800;
+  font-variant-numeric: tabular-nums;
+  letter-spacing: 0.05em;
+  padding: 6px 18px;
+  border-radius: 12px;
+  z-index: 501;
 }
 
 .timeout-placeholder {
   color: #ff9800;
-  font-size: 20vh;
+  font-size: 14vh;
   font-weight: 800;
   letter-spacing: 0.05em;
   text-transform: uppercase;
+  text-align: center;
+  line-height: 1.3;
   animation: timeout-pulse 1.2s ease-in-out infinite;
 }