fix: design QA sidebar spacing and alignment (DES-635, DES-636)

- Sub-nav horizontal padding: 24px → 28px (var(--rs-space-8))
- Remove extra bottom padding on cardWrapper
- Remove gap between top link items (Documentation/Dev Guide/API)
- Section spacing maintained at 24px

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rsbh

packages/chronicle/src/themes/default/Layout.module.css

@@ -77,6 +77,9 @@
 .topLinks {
   width: 100%;
   margin-bottom: var(--rs-space-7);
+  display: flex;
+  flex-direction: column;
+  gap: 0;
 }
 
 .topLinkItem {
@@ -135,7 +138,7 @@
 .cardWrapper {
   flex: 1;
   display: flex;
-  padding: 0 0 var(--rs-space-2) 0;
+  padding: 0;
   min-height: 0;
   background: var(--rs-color-background-base-secondary);
 }
@@ -154,7 +157,7 @@
   align-items: center;
   justify-content: space-between;
   height: var(--navbar-height);
-  padding: var(--rs-space-4) var(--rs-space-7);
+  padding: var(--rs-space-4) var(--rs-space-8);
   background: var(--rs-color-background-base-primary);
   border-bottom: 0.5px solid var(--rs-color-border-base-primary);
   backdrop-filter: blur(1px);