feat: comprehensive light theme support across entire site

- CSS foundation: theme-aware scrollbars, section glows, glass cards with
  gold shadows, stronger animated borders and glow effects for light mode
- Hero: consistent dark-video treatment for both themes, brighter gold
  gradient text, glowing CTA button
- Gradient text: auto-switch to warm gold tones on light backgrounds via
  html:not(.dark) selector
- Team profile: inverted ambient photo bg with white overlay for light,
  dark text/borders, gold-dark labels for contrast
- All sections: text-neutral-500→600 upgrades for WCAG AA contrast,
  gold shadow accents on cards (About, Pricing, FAQ, DayCard, News)
- Admin: replaced hardcoded #c9a96e with theme tokens, fixed select
  options, array editor borders, booking badges contrast
- Header: white text on transparent hero, dark text after scroll
- UI components: BackToTop, FloatingHearts, ShowcaseLayout tabs,
  SignupModal, NewsModal, GroupCard adapted for light backgrounds
- Updated CLAUDE.md to reflect dual theme support

src/app/globals.css

@@ -103,6 +103,10 @@ input[type="number"] {
 
 html {
   scrollbar-width: thin;
+  scrollbar-color: rgba(160, 160, 160, 0.5) #f5f5f5;
+}
+
+html.dark {
   scrollbar-color: rgba(201, 169, 110, 0.3) var(--color-surface-dark);
 }
 
@@ -111,14 +115,26 @@ html {
 }
 
 ::-webkit-scrollbar-track {
+  background: #f5f5f5;
+}
+
+html.dark ::-webkit-scrollbar-track {
   background: var(--color-surface-dark);
 }
 
 ::-webkit-scrollbar-thumb {
-  background: rgba(201, 169, 110, 0.3);
+  background: rgba(160, 160, 160, 0.5);
   border-radius: 4px;
 }
 
+html.dark ::-webkit-scrollbar-thumb {
+  background: rgba(201, 169, 110, 0.3);
+}
+
 ::-webkit-scrollbar-thumb:hover {
+  background: rgba(120, 120, 120, 0.6);
+}
+
+html.dark ::-webkit-scrollbar-thumb:hover {
   background: rgba(201, 169, 110, 0.5);
 }