Protocol 12: Up next (a shared queue) and where the video comes from

Up next: a server-side queue anyone edits by item id (add at end or
next, move, remove, play now, skip); each item says who added it and
how it plays. At the real end the first item swaps in after the end
card's countdown, put up by whoever can (its adder for through-me links
and files, someone with access for Jellyfin, else anyone); items that
can't play are skipped with the reason. The next item's link is
resolved ahead. Greyed "Continues with" episodes below. A chip with the
controls opens it as a popover (leaf_widgets, local path dependency for
now); "Add to queue" next to Put it up everywhere.

Delivery: the server measures the source's rate, the media's bitrate
and each member's read rate; the members card shows a source line
(who passes it on, through what, keeping up or not, source left) and
each member's route and buffer. A slow source is told once per media.
A failed server fetch is announced to everyone.

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

docs/ROADMAP.md

@@ -12,7 +12,8 @@ off by deleting it in the same commit as the code. Wire changes also edit
    ever be skipped.
 
 2. **Files**: next episode from Files (by parsed episode, with the
-   countdown). Later: tracking for file series.
+   countdown, and under Up next's "Continues with"). Later: tracking for
+   file series.
 
 3. **yt-dlp follow-ups** (see ARCHITECTURE "yt-dlp"): check that the
    bundled Windows libmpv has the ytdl hook (Lua) and plays `edl://` URLs
@@ -36,7 +37,10 @@ off by deleting it in the same commit as the code. Wire changes also edit
    filter on the Schedule from the user's AniList lists. This is the
    Schedule's personal tracking; AnimeFlow has no per-user follow.
 
-5. **Ops**: check shaders on Windows; the relay e2e "source drops
+5. **Ops**: `leaf_widgets` (the Up next popover's `LeafPopover`) is a
+   local path dependency: make it a git dependency like `fox_utils`
+   before the next release (CI cannot see the path), or go back to the
+   app's popover route. Check shaders on Windows; the relay e2e "source drops
    uncleanly and resumes" fails about half the time under the full suite.
 
 6. **Windows: first real use.** CI builds and publishes
@@ -52,8 +56,6 @@ off by deleting it in the same commit as the code. Wire changes also edit
      over instead of the buffer running dry.
    - "Bob can't open this link — relay it?": offer the relay to whoever put
      a direct link up when a viewer's player fails to open it.
-   - Show who is relaying and how fast in the member list; warn the source
-     when its upload is below the media's bitrate.
 
 8. **Jellyfin** (epic, below).
 
@@ -77,19 +79,22 @@ off by deleting it in the same commit as the code. Wire changes also edit
    - HTTP: move the app's clients (Jellyfin, AniList, AnimeFlow, updater)
      to dio from `fox_utils` when touching them, for retries/interceptors.
    - TLS: document a reverse proxy in front of the server.
-   - Playlist: `queue-add`, `queue-skip`, auto-advance like a swap.
+   - Up next follow-ups (see ARCHITECTURE "Up next"): getting the first
+     item ready only resolves its link; fetching its first seconds early
+     through the relay would make relayed starts instant too. A member
+     whose reconnect lands as a new member loses its "through me" links
+     and files in the queue (skipped as gone); the key could follow the
+     member. A whole season or a pick list at once ("Add the rest of the
+     season").
    - Sidecar subtitles.
 
 ## Epic: Jellyfin
 
 What is left (the rest is in [ARCHITECTURE.md](ARCHITECTURE.md), "Jellyfin
 in a session"):
-- Queue: put several library items (a season, a pick list) up as a
-  playlist that advances like a swap (shares `queue-add` / `queue-skip`
-  with the backlog's Playlist item).
-- Auto-advance cancel for everyone: today Cancel is per screen (the
-  designated swapper's Cancel stops the swap; a seek stops all). A shared
-  cancel needs a wire message.
+- Auto-advance cancel for everyone (the next episode and Up next): today
+  Cancel is per screen (the designated swapper's Cancel stops the swap; a
+  seek stops all). A shared cancel needs a wire message.
 - Sidecar (external) subtitle streams of Jellyfin items: only embedded
   tracks are mapped to mpv today.