US-031: Responsive testing and fixes for all new components

SubNav: horizontal scroll with hidden scrollbar, 44px touch targets.
DetailPanel: close button enlarged to 44px. Touch target fixes on
CoreSkillsTile, ProjectsTile, and LastConsultationTile interactive elements.

src/components/tiles/CoreSkillsTile.tsx

@@ -71,6 +71,7 @@ function SkillRow({ skill, onClick }: SkillRowProps) {
         alignItems: 'center',
         gap: '10px',
         padding: '8px 10px',
+        minHeight: '44px',
         background: 'var(--bg-dashboard)',
         borderRadius: 'var(--radius-sm)',
         border: '1px solid var(--border-light)',
@@ -234,6 +235,7 @@ function CategorySection({
             gap: '4px',
             marginTop: '8px',
             padding: '4px 0',
+            minHeight: '44px',
             background: 'none',
             border: 'none',
             cursor: 'pointer',