Remove local patterns CSS and Buttons patterns page

dev-server/ui-playground/index.js

 import { startApp } from '@hypothesis/frontend-shared/lib/pattern-library';
-import ButtonPatterns from './components/ButtonPatterns';
 
 import { sidebarIcons } from '../../src/sidebar/icons';
 
 /** @type {import('@hypothesis/frontend-shared/lib/pattern-library').PlaygroundRoute[]} */
-const extraRoutes = [
-  {
-    route: '/buttons',
-    title: 'Buttons',
-    component: ButtonPatterns,
-    group: 'components',
-  },
-];
+const extraRoutes = [];
 
 startApp({ baseURL: '/ui-playground', extraRoutes, icons: sidebarIcons });

src/styles/frontend-shared.scss

-// Extensions and/or overrides to shared component styles from the
-// `@hypothesis/frontend-shared` package
-
-@use '../variables' as var;
-
-// Similar to `.LinkButton`, with inline layout (so button can be used
-// within text)
-.InlineLinkButton {
-  display: inline;
-}
-
-.InlineLinkButton--underlined {
-  text-decoration: underline;
-}
-
-// An IconButton, but override minimum height/width on touch screen devices
-.NonResponsiveIconButton {
-  @media (pointer: coarse) {
-    min-width: auto;
-    min-height: auto;
-  }
-}
-
-// Links
-
-// Styling for a Link that contains only an Icon and no text. Override coloring
-// and add some padding
-.IconOnlyLink {
-  padding: var.$layout-space;
-  color: var.$grey-7;
-  &:hover:not([disabled]) {
-    color: var.$grey-7;
-  }
-}

src/styles/sidebar/components/_index.scss

@@ -4,9 +4,6 @@
 // -----------------
 @use '@hypothesis/frontend-shared/styles';
 
-// Extensions and overrides to patterns from `frontend-shared`
-@use '../../frontend-shared';
-
 // UI (Preact) Components
 // ----------
 @use './StyledText';

src/styles/ui-playground/ui-playground.scss

 // Shared pattern-library styles
 @use '@hypothesis/frontend-shared/styles/pattern-library';
-
-// Local overrides to frontend-shared styling
-@use '../frontend-shared';