[Test] Build Priority Lab route with ranking panels

[iamasx]

Summary

Build a priority-lab route that shows ranked work items, comparison notes, and a compact signal summary section.

Scope

• Add a new priority-lab route.
• Create mock priority, comparison, and signal-summary data.
• Build ranked item cards, comparison notes, and a small summary section.

Acceptance Criteria

• The route displays ranked work content clearly.
• Comparison and signal details are visible.
• The layout works across common breakpoints.
• Tests cover the key render paths.

[iamasx]

Implementation plan:

• Add the priority-lab route shell and route-specific mock data.
• Build ranked-item, comparison-note, and signal-summary components.
• Assemble the page with a concise prioritization-focused layout.
• Add styling polish and route-level tests.
• Run the standard local checks before finishing.