Default a fresh install to 3:00 + 12s

The reserve was already three minutes; only the delay moves, 15s to 12s,
which is the control both of the other presets use.

It is a default, not a migration: store.num only falls back when nothing
is saved, so anyone already carrying a bg.delay keeps it. Checked both
ways — an empty profile comes up with 12s and the 3m/12s preset already
lit, a profile holding 15000 comes up unchanged with 3m/15s lit.

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

public_html/README.md

@@ -2,7 +2,7 @@
 
 A two-player match clock with **simple delay you can actually see**. Reserve time
 plus a fixed number of free seconds each turn that never carry over — the
-Backgammon Galaxy control. Defaults to 3:00 + 15s.
+Backgammon Galaxy control. Defaults to 3:00 + 12s.
 
 Plain HTML, CSS and JavaScript. No frameworks, no fonts, no images, no network.
 
@@ -123,7 +123,7 @@ numbers and it comes back on.
 | --- | --- | --- |
 | Match | 1 – 29 points, odd | 1 |
 | Time | 0:15 – 99:00 per point | 3:00 |
-| Delay | 0 – 60 s | 15 s |
+| Delay | 0 – 60 s | 12 s |
 | Colour | Sage, Brass, Slate, Teal, Plum | Sage |
 | Sound | on / off | on |
 

public_html/index.html

@@ -556,7 +556,7 @@
 
   var cfg = {
     base:   store.num("bg.base", 180000),      // reserve per point
-    delay:  store.num("bg.delay", 15000),
+    delay:  store.num("bg.delay", 12000),
     points: store.num("bg.points", 1),         // match length, odd, 1..29
     theme:  store.get("bg.theme", "sage"),
     sound:  store.get("bg.sound", "1") === "1"

public_html/sw.js

@@ -1,5 +1,5 @@
 /* Cache-first: once installed the clock never touches the network again. */
-const CACHE = "bgclock-v9";
+const CACHE = "bgclock-v10";
 const FILES = [
   "./",
   "./index.html",