Carry playing live streams directly across sites (#802)

ddiff --git a/public/js/channel-embed.js b/public/js/channel-embed.js
iindex 4fe5dc89..7a319d63 100644
---- a/public/js/channel-embed.js
++++ b/public/js/channel-embed.js
@@@ -6,15 +6,24 @@
      const allowedOrigin = (origin) => safeOrigins.has(origin) || /^https:\/\/(?:[a-z0-9-]+\.)+openvibe\.website$/.test(origin);
      let state = { live: false, muted: true, playing: false, title: '', username: user, viewers: 0 };
      let currentStreamId = null;
++    let requestedSound = false;
      const approved18 = new Set();
      const send = () => { if (parent !== window) parent.postMessage({ type: 'ov-embed', event: 'state', ...state }, '*'); };
      const paint = () => { document.getElementById('live').hidden = !state.live; send(); };
      const setMuted = (muted) => {
          const wanted = !!muted;
++        requestedSound = !wanted;
          if (state.muted !== wanted) document.getElementById('btn-volume')?.click();
          window.OVChannelEmbedForceMuted = wanted;
          video.muted = wanted;
--        if (!wanted) video.play().catch(() => {});
++        if (!wanted && (video.srcObject || video.currentSrc)) video.play().catch(() => {
++            // A newly loaded cross-site document may need another tap for sound.
++            requestedSound = false;
++            window.OVChannelEmbedForceMuted = true;
++            video.muted = true;
++            state.muted = true;
++            send();
++        });
          state.muted = wanted;
          send();
      };
@@@ -39,10 +48,10 @@
      });
      const start = (stream) => {
          currentStreamId = stream.id;
--        state.muted = true;
++        state.muted = !requestedSound;
          state.playing = true;
--        window.OVChannelEmbedForceMuted = true;
--        video.muted = true;
++        window.OVChannelEmbedForceMuted = !requestedSound;
++        video.muted = !requestedSound;
          document.getElementById('offline').style.display = 'none';
          initPlayer(stream);
      };
ddiff --git a/public/js/ov-mini-player.js b/public/js/ov-mini-player.js
iindex 0efb9bc6..be89c0b7 100644
---- a/public/js/ov-mini-player.js
++++ b/public/js/ov-mini-player.js
@@@ -415,12 +415,31 @@
              if (!on || !st.user) { O.declare('live', null); return; }
              const u = encodeURIComponent(st.user);
              O.declare('live', {
--                src: `${location.origin}/embed/${u}`, title: st.title, live: true, href: `${location.origin}/@${u}`,
++                src: `${location.origin}/embed/${u}`, title: st.title, live: true, sound: !!(st.video || document.getElementById('video-element')) && !(st.video || document.getElementById('video-element')).muted,
++                href: `${location.origin}/@${u}`,
                  side: { src: `${location.origin}/popout/${u}`, title: `${st.title} \u00b7 chat` },
              });
          }).catch(() => { /* the overlay host could not load: the mini player still works here */ });
      }
  
++    // A direct jump from a playing channel to another OpenVibe site also carries the
++    // stream. The mini player is only created for routes within Live.
++    document.addEventListener('playing', (event) => {
++        if (event.target?.id !== 'video-element' || st.box || !isChannelPath(location.pathname)) return;
++        const match = /^\/@([^/?#]+)/.exec(location.pathname);
++        if (!match) return;
++        st.user = decodeURIComponent(match[1]);
++        st.title = (document.getElementById('ch-display-name')?.textContent || '').trim()
++            || (document.getElementById('ch-stream-title')?.textContent || '').trim() || st.user;
++        declare(true);
++    }, true);
++    document.addEventListener('pause', (event) => {
++        if (event.target?.id === 'video-element' && !st.box) declare(false);
++    }, true);
++    document.addEventListener('volumechange', (event) => {
++        if (event.target?.id === 'video-element' && st.user && isPlaying()) declare(true);
++    }, true);
++
      /** The viewer closed it: the player goes away for good. */
      function closeForGood() {
          if (typeof destroyPlayer === 'function') { try { destroyPlayer(); } catch { /* */ } }
ddiff --git a/test/channel-embed.test.js b/test/channel-embed.test.js
iindex ed8f2ffe..37084850 100644
---- a/test/channel-embed.test.js
++++ b/test/channel-embed.test.js
@@@ -56,24 +56,29 @@ assert.strictEqual(video.muted, false, 'allowlisted parent can control playback'
      if (oldDbModule) require.cache[dbPath] = oldDbModule; else delete require.cache[dbPath];
      if (oldEgressModule) require.cache[egressPath] = oldEgressModule; else delete require.cache[egressPath];
  
--    const simulate = async (payload) => {
++    const simulate = async (payload, preSound = false) => {
          const elements = Object.fromEntries(['video-element', 'live', 'offline', 'gate', 'continue', 'video-container', 'btn-volume', 'btn-play-pause'].map((id) => [id, { hidden: false, style: {}, addEventListener() {}, click() {} }]));
          const playerCalls = [];
          const sent = [];
++        let message;
          const browser = {
              window: { __OV_EMBED_ORIGINS: ['https://openvibe.live'] },
              parent: { postMessage(data, target) { sent.push({ data, target }); } }, location: { pathname: '/embed/alice' },
--            document: { getElementById(id) { return elements[id]; } }, addEventListener() {}, setInterval() {},
--            fetch: async () => ({ ok: true, json: async () => payload }), initPlayer(stream) { playerCalls.push(stream); },
++            document: { getElementById(id) { return elements[id]; } }, addEventListener(type, fn) { if (type === 'message') message = fn; }, setInterval() {},
++            fetch: async () => ({ ok: true, json: async () => payload }), initPlayer(stream) { playerCalls.push({ stream, muted: elements['video-element'].muted, forceMuted: browser.window.OVChannelEmbedForceMuted }); },
          };
          browser.window.parent = browser.parent;
          vm.runInNewContext(clientSource, browser);
++        if (preSound) message({ origin: 'https://openvibe.live', source: browser.parent, data: { type: 'ov-embed', cmd: 'unmute' } });
          await new Promise((resolve) => setImmediate(resolve));
          return { elements, playerCalls, sent };
      };
      const liveResult = await simulate({ channel: { username: 'alice', display_name: 'Alice' }, streams: [{ id: 2, is_live: true, title: 'Public show' }] });
      assert.strictEqual(liveResult.playerCalls.length, 1, 'live channel starts the shared player');
      assert.strictEqual(liveResult.sent.at(-1).data.live, true, 'live state is announced to the parent');
++    const carried = await simulate({ channel: { username: 'alice' }, streams: [{ id: 4, is_live: true }] }, true);
++    assert.strictEqual(carried.playerCalls[0].forceMuted, false, 'sound intent received before the new stream starts is preserved');
++    assert.strictEqual(carried.playerCalls[0].muted, false, 'the carried stream starts with sound when allowed');
      const offlineResult = await simulate({ channel: { username: 'alice', display_name: 'Alice' }, streams: [] });
      assert.strictEqual(offlineResult.elements.offline.style.display, 'block', 'offline channel shows the offline card');
      const gatedResult = await simulate({ channel: { username: 'alice' }, streams: [{ id: 3, is_live: true, is_nsfw: true }] });