Stream refreshed media for playback and view full

docs/media.md

@@ -154,10 +154,12 @@ that deletion is irreversible. The delete button is disabled for a 5 second coun
   shows the metadata banner below, vertical media shows it to the right, and videos carry a large
   play icon top-right. The play action embeds a YouTube, Vimeo, Twitch, or Streamable player, or
   plays a direct mp4/webm/m4v; when neither is possible it opens the external-site warning, since
-  the page is the only way to watch. **View full** opens the embedded media (player, local file,
-  or cached preview) in a new tab; the full link is a separate button that opens the original
-  page with the warning. Length comes from Discord's attachment duration and, for downloads, an
-  ffprobe probe. The status row reads
+  the page is the only way to watch. Playback and **View full** go through
+  `/api/media/<scrape>/<item>/stream`, which serves the local file or re-fetches the source message
+  for a fresh signed URL, so expired CDN links still play. Embed `videoUrl`s (gifv/Tenor mp4s) are
+  stored as `play_url` and used directly. The full link is a separate button that opens the
+  original page with the warning. Length comes from Discord's attachment duration and, for
+  downloads, an ffprobe probe. The status row reads
   `(Images/Videos) | Downloaded A/B | Cached C/B (excl Downl) | Loaded L/B`, where B is the total
   for the active filters. A scrape strip shows live progress with Stop.
   **New scrape…** (rightmost) opens a popup with Server and Group chat trees (servers expand to