fix(homepage): align container width breakpoint with grid columns

Changed width breakpoint from md to lg to match when the grid switches
to 2 columns. This prevents overflow on medium-width screens where the
container was 650px wide but still showing 1-column layout.

Now:
- Below lg: 100% width, 1 column
- At lg+: 650px width, 2 columns

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/app/page.tsx

@@ -188,7 +188,7 @@ export default function HomePage() {
                   <div
                     className={css({
                       flex: '0 0 auto',
-                      w: { base: '100%', md: '650px' },
+                      w: { base: '100%', lg: '650px' },
                     })}
                   >
                     <h3