feat(cast): music on the TV, the music bar as its remote

A cast button in Music's toolbar and in the music bar. With a television
chosen, each decrypted track goes to the relay with its cover — found as the
album card finds it — and plays there as music with its title, artist and
album; the bar's play, pause, seek, previous and next drive the receiver, its
clock is the receiver's, and the end of a track there moves the queue on.
A film or a photo taking the television pauses the bar; stopping the cast
carries the track on locally.

Photos and tracks now share one path: a whole file sent to the relay in
pieces (binary frames on Android, written to disk there), served at /file
with byte ranges and its cover at /cover, and loaded as what the relay says
it is. cast:image is gone; cast:chromecast:seek is new.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/style.css b/packages/meshbay-hub/src/meshbay_hub/static/style.css
index 9be414f..9383043 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/style.css
+++ b/packages/meshbay-hub/src/meshbay_hub/static/style.css
@@ -2054,6 +2054,8 @@ button:disabled { opacity: 0.5; cursor: not-allowed; }
    any other menu there, hung under the button rather than at a point. */
 .cast-btn.casting { color: var(--accent); border-color: var(--accent); }
 .ctx-menu.cast-menu { position: absolute; top: calc(100% + 4px); right: 0; z-index: 150; }
+/* From the music bar, at the bottom of the window: the menu opens upward. */
+.cast-menu-up { top: auto !important; bottom: calc(100% + 4px); }
 .ctx-menu-item.cast-menu-current { color: var(--text-dim); cursor: default; }
 .ctx-menu-item.cast-menu-current:hover { background: none; }
 .ctx-menu-item svg { width: 16px; height: 16px; flex-shrink: 0; }