feat(cast): photos on the TV, and a television chosen once for the session

A cast button in Videos' toolbar, at the top of Photos, in an album's bar and
in the lightbox, in a group and in Search alike. A television chosen there is
kept for the session: a film opened plays on it with the player as its remote
from the start, and a photo opened in the lightbox is shown on it, scaled to
1920x1080, upright, as JPEG. The lightbox gains a slideshow.

The relay serves one photo at /image behind the stream's token, on the desktop
and on Android; the shell, not the page, decides that the receiver loads it as
a picture.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/video-player.js b/packages/meshbay-hub/src/meshbay_hub/static/video-player.js
index 2c424fb..ed1f18c 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/video-player.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/video-player.js
@@ -6,6 +6,7 @@ import { Icon } from './icon.js';
 import { formatSize, CHUNK_SIZE, pipelinedDownload } from './file-utils.js';
 import { loadAuth } from './hub-client.js';
 import * as platform from './platform.js';
+import { castSession } from './cast-session.js';
 
 // Seconds of already-watched video kept in the SourceBuffer, and the queue depth
 // past which we start making room before being forced to.
@@ -484,17 +485,22 @@ function VideoPlayer({ entry, transportRef, gekRef, onClose, onDownload }) {
   // Where the stream the node is sending begins, in film time. The same number
   // the SourceBuffer gets as its `timestampOffset`.
   const streamStartRef = useRef(0);
-  const [castActive, setCastActive] = useState(false);
+  // A television already chosen this session (cast-session.js) takes the film
+  // from its first segment: the cast starts as a restart would, pending until
+  // the init segment arrives, and the player opens as its remote. Read once —
+  // a television chosen while this film plays is chosen here, by the picker.
+  const [autoCast] = useState(() => (castSession.supported ? castSession.device : null));
+  const [castActive, setCastActive] = useState(Boolean(autoCast));
   const [castUrl, setCastUrl] = useState(null);
   const [castPickerOpen, setCastPickerOpen] = useState(false);
   const [castDevices, setCastDevices] = useState([]);
   const [castScanning, setCastScanning] = useState(false);
-  const [castDeviceName, setCastDeviceName] = useState(null);
-  const castActiveRef = useRef(false);
+  const [castDeviceName, setCastDeviceName] = useState(autoCast ? autoCast.name : null);
+  const castActiveRef = useRef(Boolean(autoCast));
   const castCodecRef = useRef(null);
   const initSegmentRef = useRef(null);
-  const castRestartPendingRef = useRef(false);
-  const castDeviceRef = useRef(null);
+  const castRestartPendingRef = useRef(Boolean(autoCast));
+  const castDeviceRef = useRef(autoCast);
   const castRestartGenRef = useRef(0);
   // The receiver as last polled: { playerState, position } with the position
   // on the film's timeline, or null before it has answered.
@@ -1758,7 +1764,10 @@ function VideoPlayer({ entry, transportRef, gekRef, onClose, onDownload }) {
     return () => { stopped = true; clearInterval(id); };
   }, [remoteMode]);
 
+  // Stopping here is stopping for the session: the next film or photo stays
+  // on this device until a television is chosen again.
   const stopCast = async () => {
+    castSession.forget();
     await platform.cast.chromecastDisconnect().catch(() => {});
     await platform.cast.stop();
     setCastActive(false); castActiveRef.current = false;
@@ -1896,6 +1905,7 @@ function VideoPlayer({ entry, transportRef, gekRef, onClose, onDownload }) {
                 ${castDevices.map(d => html`
                   <button class="cast-picker-item" onClick=${() => {
                     setCastPickerOpen(false);
+                    castSession.choose(d);
                     setCastDeviceName(d.name);
                     setCastActive(true); castActiveRef.current = true;
                     castRestartPendingRef.current = true;