Rename the site to pl8list rewind with a dubplate mark

The infinity sign becomes a dubplate: a wobbling riddim groove around a red label
with a rewind arrow, after the soundsystem rewind where a tune the dance loves is
pulled back and run again. Icons, manifest, titles, legal pages and the README use
the new name; cookie names, storage keys and the link key info keep pl8inf so no
one is signed out or loses settings.

README.md

@@ -1,9 +1,12 @@
-# pl8list ∞
+# pl8list rewind
 
 An endless, TikTok-style scroll through [pl8list](https://pl8list.com), with its own
 recommendation algorithm that learns from what you like, finish and skip. Sign in with
 your pl8list account; each user gets their own feed and taste profile.
 
+The name is the soundsystem rewind: when a dance loves a tune, the selector pulls the
+plate back and runs it again. Here, what you like comes back.
+
 Not affiliated with pl8list.
 
 ![Feed on desktop](docs/feed-desktop.png)