feat(ui): add 'All' quick filter to Issues list

Adds an 'All' option to the quick filter presets that shows issues
of all statuses without any status filtering applied.

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

ui/src/components/IssuesList.tsx

@@ -44,6 +44,7 @@ const defaultViewState: IssueViewState = {
 };
 
 const quickFilterPresets = [
+  { label: "All", statuses: [] as string[] },
   { label: "Active", statuses: ["todo", "in_progress", "in_review", "blocked"] },
   { label: "Backlog", statuses: ["backlog"] },
   { label: "Done", statuses: ["done", "cancelled"] },