fix(ui): center skills empty state and fix terminal toolbar overlap (#1064)

* fix(ui): center skills empty state and fix terminal toolbar overlap

Fix two UI layout issues in the settings and terminal views.

Skills empty state:

- Add h-full to the max-w-3xl content wrapper so flex centering works

- Make book icon responsive (h-10 w-10 sm:h-12 sm:w-12)

- Add px-4 padding for narrow viewports

Terminal toolbar:

- Reserve right padding (pr-20) for dock fullscreen/close buttons

- Remove pb-1 from quick keys to fix vertical misalignment

- Change shrink-0 to min-w-0 for graceful shrinking on narrow widths

* ref(ui): gate pr-20 padding on desktop runtime only

packages/ui/src/components/sections/skills/SkillsPage.tsx

@@ -357,9 +357,9 @@ const SkillsInstalledPage: React.FC = () => {
 
   if ((!selectedSkillName && !skillDraft) || hasStaleSelection) {
     return (
-      <div className="flex h-full items-center justify-center">
+      <div className="flex h-full items-center justify-center px-4">
         <div className="text-center text-muted-foreground">
-          <RiBookOpenLine className="mx-auto mb-3 h-12 w-12 opacity-50" />
+          <RiBookOpenLine className="mx-auto mb-3 h-10 w-10 sm:h-12 sm:w-12 opacity-50" />
           <p className="typography-body">{t('settings.skills.page.empty.title')}</p>
           <p className="typography-meta mt-1 opacity-75">{t('settings.skills.page.empty.description')}</p>
         </div>
@@ -369,7 +369,7 @@ const SkillsInstalledPage: React.FC = () => {
 
   if (isLoading) {
     return (
-      <div className="flex h-full items-center justify-center">
+      <div className="flex h-full items-center justify-center px-4">
         <div className="text-center text-muted-foreground">
           <p className="typography-body">{t('settings.skills.page.loading.details')}</p>
         </div>