New SummaryPreviewScreen renders the generated PDF page by page with
the platform PdfRenderer (2x scale, no new dependencies) and puts share
in the top bar — see before you send. The settings button now opens the
preview instead of jumping straight to the share sheet; the share path
reuses the already-rendered file via DoctorSummaryPdf.shareIntentFor.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
