Fix MDX lint errors by replacing backticks with code tags

Replace backticks in TableCell components with <code> tags to fix MDX parsing issues:
- typography/page.mdx: Fix property names and examples
- breakpoints/page.mdx: Fix breakpoint names
- group-selector/page.mdx: Fix selector names and role attribute

Author: claude

apps/landing/src/app/(detail)/docs/api/group-selector/page.mdx

@@ -44,19 +44,19 @@ Add `role="group"` to a parent element, then use `_groupHover`, `_groupFocus`, o
   </TableHead>
   <TableBody>
     <TableRow>
-      <TableCell>`_groupHover`</TableCell>
-      <TableCell>Parent with `role="group"` is hovered</TableCell>
+      <TableCell><code>_groupHover</code></TableCell>
+      <TableCell>Parent with <code>role="group"</code> is hovered</TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`_groupFocus`</TableCell>
-      <TableCell>Parent with `role="group"` is focused</TableCell>
+      <TableCell><code>_groupFocus</code></TableCell>
+      <TableCell>Parent with <code>role="group"</code> is focused</TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`_groupActive`</TableCell>
-      <TableCell>Parent with `role="group"` is active (pressed)</TableCell>
+      <TableCell><code>_groupActive</code></TableCell>
+      <TableCell>Parent with <code>role="group"</code> is active (pressed)</TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`_groupFocusWithin`</TableCell>
+      <TableCell><code>_groupFocusWithin</code></TableCell>
       <TableCell>Any element inside the group receives focus</TableCell>
     </TableRow>
   </TableBody>

apps/landing/src/app/(detail)/docs/devup/breakpoints/page.mdx

@@ -32,37 +32,37 @@ Devup UI uses a mobile-first responsive design system with 6 breakpoints. Use ar
   <TableBody>
     <TableRow>
       <TableCell>0</TableCell>
-      <TableCell>`xs`</TableCell>
+      <TableCell><code>xs</code></TableCell>
       <TableCell>0px - 479px</TableCell>
       <TableCell>Mobile (portrait)</TableCell>
     </TableRow>
     <TableRow>
       <TableCell>1</TableCell>
-      <TableCell>`sm`</TableCell>
+      <TableCell><code>sm</code></TableCell>
       <TableCell>480px - 767px</TableCell>
       <TableCell>Mobile (landscape)</TableCell>
     </TableRow>
     <TableRow>
       <TableCell>2</TableCell>
-      <TableCell>`md`</TableCell>
+      <TableCell><code>md</code></TableCell>
       <TableCell>768px - 991px</TableCell>
       <TableCell>Tablet</TableCell>
     </TableRow>
     <TableRow>
       <TableCell>3</TableCell>
-      <TableCell>`lg`</TableCell>
+      <TableCell><code>lg</code></TableCell>
       <TableCell>992px - 1279px</TableCell>
       <TableCell>Small desktop</TableCell>
     </TableRow>
     <TableRow>
       <TableCell>4</TableCell>
-      <TableCell>`xl`</TableCell>
+      <TableCell><code>xl</code></TableCell>
       <TableCell>1280px - 1599px</TableCell>
       <TableCell>Desktop</TableCell>
     </TableRow>
     <TableRow>
       <TableCell>5</TableCell>
-      <TableCell>`2xl`</TableCell>
+      <TableCell><code>2xl</code></TableCell>
       <TableCell>1600px+</TableCell>
       <TableCell>Large desktop</TableCell>
     </TableRow>

apps/landing/src/app/(detail)/docs/devup/typography/page.mdx

@@ -80,39 +80,39 @@ Each typography style can include:
   </TableHead>
   <TableBody>
     <TableRow>
-      <TableCell>`fontFamily`</TableCell>
+      <TableCell><code>fontFamily</code></TableCell>
       <TableCell>Font family name</TableCell>
-      <TableCell>`"Pretendard"`</TableCell>
+      <TableCell><code>"Pretendard"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`fontSize`</TableCell>
+      <TableCell><code>fontSize</code></TableCell>
       <TableCell>Font size</TableCell>
-      <TableCell>`"16px"`</TableCell>
+      <TableCell><code>"16px"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`fontWeight`</TableCell>
+      <TableCell><code>fontWeight</code></TableCell>
       <TableCell>Font weight (number or string)</TableCell>
-      <TableCell>`700` or `"bold"`</TableCell>
+      <TableCell><code>700</code> or <code>"bold"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`fontStyle`</TableCell>
+      <TableCell><code>fontStyle</code></TableCell>
       <TableCell>Font style</TableCell>
-      <TableCell>`"normal"` or `"italic"`</TableCell>
+      <TableCell><code>"normal"</code> or <code>"italic"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`lineHeight`</TableCell>
+      <TableCell><code>lineHeight</code></TableCell>
       <TableCell>Line height (number or string)</TableCell>
-      <TableCell>`1.5` or `"150%"`</TableCell>
+      <TableCell><code>1.5</code> or <code>"150%"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`letterSpacing`</TableCell>
+      <TableCell><code>letterSpacing</code></TableCell>
       <TableCell>Letter spacing</TableCell>
-      <TableCell>`"-0.02em"`</TableCell>
+      <TableCell><code>"-0.02em"</code></TableCell>
     </TableRow>
     <TableRow>
-      <TableCell>`textTransform`</TableCell>
+      <TableCell><code>textTransform</code></TableCell>
       <TableCell>Text transformation</TableCell>
-      <TableCell>`"uppercase"`</TableCell>
+      <TableCell><code>"uppercase"</code></TableCell>
     </TableRow>
   </TableBody>
 </Table>