fix(sounds): fall back to default volume on out-of-range input

resolveVolume previously clamped any value >=1 to full blast. If a
future settings change ever leaks a 0–100 scale through (instead of
0–1), the user gets jump-scared at max volume. Treat any v>1 as a
scale-drift bug and play at DEFAULT_VOLUME instead.

Also reject NaN / Infinity explicitly rather than relying on the
<=0 branch catching them.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/utils/sounds.ts

@@ -70,9 +70,11 @@ function playChord(frequencies: number[], volume: number, stagger = 0): void {
 function resolveVolume(userVolume: number | undefined, enabled: boolean): number {
   if (!enabled) return 0;
   const v = typeof userVolume === "number" ? userVolume : DEFAULT_VOLUME;
-  // Clamp: 0 → silent, 1 → loud. Protect against bad settings.
-  if (v <= 0) return 0;
-  if (v >= 1) return 1;
+  if (!Number.isFinite(v) || v <= 0) return 0;
+  // Any value >1 means a scale drift somewhere upstream (e.g. a 0–100
+  // slider leaking through unscaled). Clamping to 1 would blast the
+  // user at full volume; fall back to DEFAULT_VOLUME instead.
+  if (v > 1) return DEFAULT_VOLUME;
   return v;
 }