Add show name and track progress bar

README.md

@@ -1,8 +1,9 @@
 # subwave-nowplaying
 
 Tronbyt/Tidbyt app showing the current track on a [SUB/WAVE](https://github.com/perminder-klair/subwave)
-internet radio station: album art, track title, artist, and station name,
-with title/artist scrolling if they don't fit.
+internet radio station: album art, track title, artist, the current show
+name, and a progress bar for the track, with title/artist scrolling if they
+don't fit.
 
 Not tied to any specific station — set your own station's base URL in the
 app's config when adding it to a device.
@@ -24,6 +25,18 @@ app's config when adding it to a device.
   instead of stale track info.
 - If a track has no `subsonic_id`, or the cover fetch fails, falls back to a
   full-width layout with no art rather than a broken image.
+- Shows the current show name (`context.activeShow.name`) below the artist,
+  and a track progress bar at the bottom.
+
+**Progress bar caveat:** the now-playing API reports track `duration` but
+not elapsed/remaining time, so the app tracks playback position itself —
+the first time it sees a given `subsonic_id`, it stamps the current
+wall-clock time in pixlet's cache, then diffs against that stamp on later
+renders to compute elapsed seconds. This only works correctly on a
+long-lived server process with a persistent cache (true for
+`tronbyt/server`'s in-memory cache) — a one-shot `pixlet render` CLI
+invocation always starts a fresh process with an empty cache, so the bar
+will always show 0% when testing locally. This is expected, not a bug.
 
 **Note on unreachable hosts:** if the station URL is wrong or the host is
 completely unreachable (DNS failure, connection refused), `http.get` raises