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, 9 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/platform.js b/packages/meshbay-hub/src/meshbay_hub/static/platform.js
index 0174edc..3a0c628 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/platform.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/platform.js
@@ -460,6 +460,15 @@ export const cast = {
     if (!bridge || !bridge.cast || !bridge.cast.subtitle) return null;
     return bridge.cast.subtitle(sub);
   },
+  // A photo for the receiver: `{ bytes, type }`, already scaled to the
+  // television. Absent from an older shell, so callers check `canShowImages`.
+  get canShowImages() {
+    return Boolean(bridge && bridge.cast && bridge.cast.image);
+  },
+  async image(img) {
+    if (!this.canShowImages) return null;
+    return bridge.cast.image(img);
+  },
   async finish() {
     if (!bridge || !bridge.cast) return false;
     return bridge.cast.finish();