chore: remove dead code, unused CSS, unused components, and clean up git tracking

- Remove storage/logs/ and prod.log from git tracking; add to .gitignore
- Remove unused AvatarCarousel and ArticleSlider components
- Remove unused SkeletonTable export from ui.tsx
- Remove unused ChevronDown import from admin layout
- Remove 13 unused CSS classes (icon-base, nav-*, navigation-icon*, .app.dark,
  text-body, transition-base, card-base, admin-info-grid, .coin.*)
- Remove duplicate translation keys (openMenu/closeMenu in en.json)
- Fix admin-bans to use Prisma-generated bans_type enum
- Create shared AdminPageHeader component and formatDate utility
- Add logger and generateRequestId for structured logging
- All 58 tests pass, typecheck clean, build succeeds

src/app/globals.css

@@ -159,58 +159,13 @@ body {
   }
 }
 
-/* ── Atom icons / backgrounds (asset paths adapted to /assets) ── */
-.icon-base {
-  background-repeat: no-repeat;
-  background-position: center;
-  background-size: contain;
-}
-.nav-credit-icon {
-  background: #e9b124 url("/assets/images/icons/currency/credits.png") no-repeat center;
-  outline: 1px solid #b26d18;
-}
-.nav-ducket-icon {
-  background: #c44aac url("/assets/images/icons/currency/duckets.png") no-repeat center;
-  outline: 1px solid #812378;
-}
-.nav-diamond-icon {
-  background: #caf1f3 url("/assets/images/icons/currency/diamonds.png") no-repeat center;
-  outline: 1px solid #6caff4;
-}
-.navigation-icon {
-  width: 20px;
-  height: 25px;
-  background-repeat: no-repeat;
-  background-position: center;
-}
-.navigation-icon.shop {
-  background-image: url("/assets/images/icons/navigation/shop.png");
-}
-.navigation-icon.leaderboards {
-  background-image: url("/assets/images/icons/navigation/leaderboards.png");
-}
-.navigation-icon.rules {
-  background-image: url("/assets/images/icons/navigation/rules.gif");
-}
-.navigation-icon.home {
-  background-image: url("/assets/images/icons/navigation/home.png");
-}
-.navigation-icon.community {
-  background-image: url("/assets/images/icons/navigation/community.png");
-}
-
+/* ── Site background ── */
 .site-bg {
   background:
     linear-gradient(to bottom, color-mix(in srgb, var(--color-primary) 12%, rgba(255,255,255,0.6)), rgba(255,255,255,0.75)),
     url("/assets/images/background-light.jpg") no-repeat fixed center / cover;
   background-blend-mode: overlay;
 }
-.app.dark .site-bg {
-  background:
-    linear-gradient(to bottom, color-mix(in srgb, var(--color-primary) 8%, rgba(15,17,23,0.7)), rgba(15,17,23,0.85)),
-    url("/assets/images/background-dark.jpg") no-repeat fixed center / cover;
-  background-blend-mode: overlay;
-}
 
 .article-body {
   line-height: 1.7;
@@ -227,9 +182,6 @@ body {
   text-decoration: underline;
 }
 
-.text-body {
-  color: var(--color-text);
-}
 .text-muted {
   color: var(--color-text-muted);
 }
@@ -242,9 +194,6 @@ body {
 .text-shadow-sm {
   text-shadow: 0 1px 2px rgba(0, 0, 0, 0.6);
 }
-.transition-base {
-  transition: all 0.2s ease-in-out;
-}
 .hover-lift {
   transition: transform 0.2s ease, box-shadow 0.2s ease;
 }
@@ -252,18 +201,6 @@ body {
   transform: translateY(-2px);
   box-shadow: var(--shadow-card-hover);
 }
-.card-base {
-  background-color: var(--color-navbar);
-  color: var(--color-navbar-text);
-  border-radius: var(--radius-md);
-  box-shadow: var(--shadow-card);
-  border: 1px solid color-mix(in srgb, var(--color-text-muted) 15%, transparent);
-}
-.card-base:hover {
-  box-shadow: var(--shadow-card-hover);
-  border-color: color-mix(in srgb, var(--color-text-muted) 25%, transparent);
-}
-
 /* ── App component classes (used across the converted pages) ── */
 h1 {
   font-size: var(--size-heading-h1, 30px);
@@ -442,16 +379,6 @@ tbody tr:hover {
   color: #fff;
   font-size: 0.7rem;
 }
-.coin.credits {
-  background: #e9b124;
-}
-.coin.duckets {
-  background: #c44aac;
-}
-.coin.diamonds {
-  background: #4bc0d9;
-}
-
 /* ── Admin panel (Housekeeping) ─────────────────────────────────
    Modern, consistent styling for all admin content pages. */
 .admin-page { scroll-margin-top: 1rem; }
@@ -553,12 +480,6 @@ tbody tr:hover {
   margin-top: 0;
 }
 
-/* Two-column info grid */
-.admin-info-grid {
-  display: grid;
-  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
-  gap: 0.75rem;
-}
 .admin-info-item {
   display: flex;
   flex-direction: column;