fix(ui): prevent top bar and header rows from overflowing on mobile

- BreadcrumbBar: add min-w-0/overflow-hidden to container, truncate last breadcrumb item
- IssueDetail: add flex-wrap and min-w-0 to header row, shrink-0 on buttons, truncate project name
- Companies: add flex-wrap and tighter gap on stats row for mobile

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/pages/Companies.tsx

@@ -231,7 +231,7 @@ export function Companies() {
               </div>
 
               {/* Stats row */}
-              <div className="flex items-center gap-5 mt-4 text-sm text-muted-foreground">
+              <div className="flex items-center gap-3 sm:gap-5 mt-4 text-sm text-muted-foreground flex-wrap">
                 <div className="flex items-center gap-1.5">
                   <Users className="h-3.5 w-3.5" />
                   <span>