feat: info pages — tab replacement, custom pages on /info, responsive fixes

- Add replaces_tab field to admin editor with conflict detection
- Show custom InfoPages as extra tabs on /info page
- Replace built-in tab content when replacement is configured
- Rich DOMPurify sanitizer for TipTap content (images, video, iframe)
- Fix query race: built-in queries wait for tab-replacements to load
- Horizontal scroll for tabs on mobile, 44px touch targets
- Responsive prose: scrollable tables, h-auto on img/video, light theme borders
- Loyalty tier names truncation, progress bar labels stack on mobile

src/styles/globals.css

@@ -967,6 +967,9 @@ img.twemoji {
 
   .prose table {
     @apply mb-4 w-full border-collapse;
+    display: block;
+    overflow-x: auto;
+    -webkit-overflow-scrolling: touch;
   }
 
   .prose th {
@@ -978,7 +981,7 @@ img.twemoji {
   }
 
   .prose img {
-    @apply my-4 max-w-full rounded-xl;
+    @apply my-4 h-auto max-w-full rounded-xl;
   }
 
   .prose mark {
@@ -989,6 +992,10 @@ img.twemoji {
     @apply my-4 block aspect-video w-full max-w-2xl rounded-xl;
   }
 
+  .prose video {
+    @apply my-4 block h-auto w-full max-w-full rounded-xl;
+  }
+
   /* Light theme prose styles */
   .light .prose {
     @apply text-champagne-800;
@@ -1070,6 +1077,14 @@ img.twemoji {
     @apply border border-champagne-300;
   }
 
+  .light .prose video {
+    @apply border border-champagne-300;
+  }
+
+  .light .prose img {
+    @apply border border-champagne-300;
+  }
+
   /* Support for plain text with line breaks */
   .prose-plain {
     @apply whitespace-pre-line;