feat(website): drop the tmux bar from the hero demo

The demo is the client, not the terminal it happens to run in. Removing the
bar takes the tmux window list, session name, host and clock with it, plus
the three --tmux-* tokens that existed only to paint it.

The scale floor goes too: the terminal now shrinks to whatever width it is
given instead of stopping at half size and scrolling sideways, which makes
useFitScale's minScale parameter and the media query feeding it dead weight.

website/src/index.css

@@ -150,11 +150,6 @@
   --tui-track: #2a2622;
   --tui-bezel: #000000;
 
-  /* tmux's own status bar. Emulator chrome, so it does not follow the theme. */
-  --tmux-bg: #0e0c0a;
-  --tmux-hl: #b9a6e8;
-  --tmux-hl-fg: #1a1526;
-
   color-scheme: dark;
 }
 
@@ -223,10 +218,6 @@
  * is what the Rust client does. Those names do not flip with the theme, so on
  * manila they would leave paper-on-paper. Light mode re-cuts the same names
  * darker, scoped to the terminal's content.
- *
- * Deliberately not applied to the tmux bar above it: that is the emulator's
- * own chrome, it keeps its near-black background in both themes, and needs
- * the bright phosphor to stay legible against it.
  */
 [data-theme='light'] .tui-content {
   --color-paper: #14110f;