Interface ScreenshotStrategyHooks

Hooks the Panel must expose so the strategy can:

• hideAllPanels: hide the recording panel + others before capture
• downloadBlob: trigger a file download (routed through Panel's wrapper so existing test spies still see the call)
• generateFilename: format the timestamped filename (kept on Panel so the format stays consistent across capture paths)

Kept as a callback object (not a Panel reference) so the strategy has zero structural coupling to the orchestrator.