fix(layout): sidebar/header 對齊 — ml-[224px] + pt-[68px] 消除 32px 空隙

- ml-64(256px) → ml-[224px] 對齊 sidebar 實際寬度
- pt-16(64px) → pt-[68px] 對齊 header 實際高度
- calc(100vh-64px) → calc(100vh-68px)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/app/[locale]/page.tsx

@@ -508,7 +508,7 @@ export default function Home({ params }: { params: { locale: string } }) {
       <div style={{
         display: 'flex',
         flexDirection: 'column',
-        height: 'calc(100vh - 64px)',
+        height: 'calc(100vh - 68px)',
         background: '#f5f4ed',
         fontFamily: 'var(--font-body), monospace',
         overflow: 'hidden',

apps/web/src/components/layout/app-layout.tsx

@@ -131,9 +131,9 @@ export function AppLayout({
       <main
         className={cn(
           'relative z-10',
-          'pt-16', // Header height (64px)
+          'pt-[68px]',
           'transition-all duration-300 ease-out',
-          collapsed ? 'ml-16' : 'ml-64'
+          collapsed ? 'ml-16' : 'ml-[224px]'
         )}
       >
         {fullBleed ? (