US-5.9implemented Sticky toolbar with keyboard shortcuts
As a user who scrolls through large dashboards with many plots I want the toolbar (title, period selector, drill-down button, back button) to stay fixed at the top of the viewport, and keyboard shortcuts to toggle drill-down mode and go back so that I can always access controls without scrolling back to the top.
Acceptance Criteria
- The toolbar uses `position: sticky; top: 0` and stays visible while scrolling.
- Pressing `d` toggles drill-down mode on/off.
- Pressing `Escape` clicks the "Back to Overview" button when it is visible.
- Keyboard shortcuts are ignored when typing in input fields, textareas, or the dropdown search box.
No DAG diagram: Pure UI/UX enhancement on the Dash presentation layer; no data-flow change.
Demo video coming soon