Refactor sidebar (#6971)

* Refactor RightNav

(cherry picked from commit 96bb02acfd2d7452df18a0e7410e6a7169a583ed)

* Better gutter handling

* Clean up styles

* Memoize breakpoints

* Format

* Comment

* Loosen spacing, handle overflow, smaller text to match prod

* Fix circular imports on native

* Return 0 instead of undefined for easier calculations

* Re-assign

* Fix

* Port over fix from subs/base

* Space out right nav feeds, widen sidebar to match prod

* Fix lost padding on home header

* Fix perf by not actually linking to new URL

* Remove underline on focus

* Foramt

---------

Co-authored-by: Dan Abramov <dan.abramov@gmail.com>

src/view/shell/desktop/Search.tsx

@@ -225,12 +225,12 @@ export function DesktopSearch() {
 const styles = StyleSheet.create({
   container: {
     position: 'relative',
-    width: 300,
+    width: '100%',
   },
   resultsContainer: {
     marginTop: 10,
     flexDirection: 'column',
-    width: 300,
+    width: '100%',
     borderWidth: 1,
     borderRadius: 6,
   },