A row of toggle chips below the filter box — one per pql ticket type,
ordered large→small (Initiative, Epic, Story, Task, Bug), each with its
TicketTypeColors dot + border. Single-click toggles a type; double-click
isolates it (chart-legend solo, fully reversible); disabling the last
enabled type snaps all back on so the list is never blank. ANDed with the
text filter; all on by default, nothing persisted.
One GestureDetector owns both onTap + onDoubleTap so Flutter disambiguates
single vs double. Wireframe updated + approved.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>