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/components/common/actor-avatar.tsx

@@ -33,7 +33,7 @@ function ActorAvatar({
     <div
       className={cn(
         "inline-flex shrink-0 items-center justify-center rounded-full font-medium",
-        isAgent ? "bg-info/10 text-info" : "bg-muted text-muted-foreground",
+        "bg-muted text-muted-foreground",
         className
       )}
       style={{ width: size, height: size, fontSize: size * 0.45 }}