Hide the score line and score icon in a one-point match

A single game has no match to keep score of, so showing "Score: 0 - 0, out
of 1" and a sheet to edit it was just clutter. Both are hidden while the
match is one point and come back at three or more.

`hidden` alone doesn't do it for the button: .btn sets display:grid, and an
author rule beats the UA's [hidden] rule whatever the specificity — the same
trap behind the original both-icons-showing bug — so .btn[hidden] has to say
it explicitly. The markup carries hidden by default too, so the common
one-point case can't flash the score before the script runs.

The bar returns to its original spacing when the icon goes: the two .75
gaps either side of it merge back into the 1.5 it had before.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

public_html/README.md

@@ -68,6 +68,10 @@ Set **Match** in the settings to the number of points you're playing to — 1, 3
 5 and up to 29. The time you set is *per point*, so a 5-point match at 2:00 a
 point puts 10:00 on each clock, and the settings sheet shows you that sum.
 
+At **1 point** there's no match to keep score of, so the score line and the
+score-sheet icon both disappear and you get the plain single-game clock. Set
+the match to 3 or more and they come back.
+
 The score sheet is the middle icon in the bar. It reads **You** for whoever is
 holding the phone — the bottom half — and **Them** for the far end, and each
 panel shows its own score first, so both players read their own score on the