refactor: Clean up unused clipboard handler and dead code in ResultDashboard #230

In src/features/comparison/components/result-dashboard.tsx, clipboard copying logic is defined but never rendered.

Motivation

Unused hooks and dead functions clutter the component and confuse contributors. We should either wire this up to an active button or clean up the unused state.

Tasks

• Inspect result-dashboard.tsx lines 65 and 113-128 (useClipboardCopy and handleCopy).
• Either:
  • Option A (Recommended): Add a small 'Copy Raw JSON' / 'Debug Data' action button or dropdown item that invokes handleCopy for developers needing raw payload data.
  • Option B: Remove the unused handleCopy, copied, and unused icon imports (Check, Copy).
• Run pnpm lint and npx tsc --noEmit to ensure clean code.