design: lighten v2 overlay so the harbor is actually visible

Overlay was 0.72 multiply with very dark color-bg, which crushed the
photo to invisible. Dropped to 0.48 + bumped photo brightness 0.42→0.60.

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

public/css/wevisto-design.css

@@ -107,7 +107,7 @@
   position: fixed;
   inset: 0;
   background: url('/build/assets/harbor.jpg') center/cover no-repeat;
-  filter: brightness(0.42) saturate(0.85);
+  filter: brightness(0.6) saturate(0.9);
   z-index: -3;
 }
 [data-design="v2"] body::after {
@@ -115,9 +115,9 @@
   position: fixed;
   inset: 0;
   background:
-    radial-gradient(ellipse 80% 70% at 50% 50%, transparent 0%, rgba(0,0,0,0.45) 100%),
+    radial-gradient(ellipse 90% 75% at 50% 50%, transparent 0%, rgba(0,0,0,0.35) 100%),
     var(--color-bg);
-  opacity: 0.72;
+  opacity: 0.48;
   mix-blend-mode: multiply;
   z-index: -2;
   pointer-events: none;