feat(ui): restyle issue status and priority with colored badges

- Status labels use colored pill badges (solid bg for active, muted for inactive)
- Board columns have tinted backgrounds matching their status color
- Priority badges use orange (--priority) design token for clear distinction from status
- Issue cards restructured: identifier, title, then assignee/priority/date row
- Agent avatar default color changed from blue to gray
- New Issue button in header changed to solid/primary style
- Reduced hover shadow on board cards
- Added inheritColor prop to StatusIcon and PriorityIcon for badge use

apps/web/features/issues/components/issues-header.tsx

@@ -310,7 +310,6 @@ export function IssuesHeader() {
         </span>
         {/* New issue */}
         <Button
-          variant="outline"
           size="sm"
           onClick={() => useModalStore.getState().open("create-issue")}
         >