Enhance public access and error handling in site-related views and loaders

- Updated `DebugScopedRateThrottle` to allow public access for blueprint list requests with site filters.
- Modified `SiteViewSet` and `SiteBlueprintViewSet` to permit public read access for list requests.
- Enhanced `loadSiteDefinition` to resolve site slugs to IDs, improving the loading process for site definitions.
- Improved error handling in `SiteDefinitionView` and `loadSiteDefinition` for better user feedback.
- Adjusted CSS styles for better layout and alignment in shared components.

frontend/src/components/shared/blocks/blocks.css

@@ -6,6 +6,8 @@
   display: flex;
   flex-direction: column;
   gap: 1rem;
+  align-items: center;
+  text-align: center;
 }
 
 .shared-hero__eyebrow {
@@ -36,7 +38,7 @@
   font-weight: 600;
   color: #0f172a;
   background: #fff;
-  align-self: flex-start;
+  align-self: center;
   cursor: pointer;
 }
 

frontend/src/components/shared/layouts/layouts.css

@@ -2,16 +2,19 @@
   display: flex;
   flex-direction: column;
   gap: 1.5rem;
+  width: 100%;
 }
 
 .shared-layout__hero {
   min-height: 320px;
+  width: 100%;
 }
 
 .shared-layout__body {
   display: grid;
   grid-template-columns: minmax(0, 1fr);
   gap: 1.25rem;
+  width: 100%;
 }
 
 @media (min-width: 1024px) {
@@ -22,6 +25,18 @@
 
 .shared-layout__section {
   margin-bottom: 1.25rem;
+  text-align: center;
+}
+
+.shared-layout__section > * {
+  text-align: left;
+  max-width: 100%;
+}
+
+.shared-layout__section h2,
+.shared-layout__section h3,
+.shared-layout__section h4 {
+  text-align: center;
 }
 
 .shared-layout__sidebar {