Problem: changing .preview-modal from height to max-height broke iframe
previews - <iframe style='flex:1'> needs a concrete ancestor height, which
max-height alone doesn't supply when content is shorter than the cap.
Fix - CSS:
.preview-modal--full { height: 88vh } applied to non-tweet modals
.preview-modal--full .preview-modal-body { max-height: none }
.preview-iframe-toolbar span: remove text-transform/letter-spacing
(was uppercasing the URL/title in shouty caps)
Fix - PreviewModal: className adds --full when entity_kind is not
tweet/tweet_thread; tweet previews keep shrink-to-fit behavior.
Fix - PreviewPanel: pass title + original_url from summary to IframePreview
for both HTML and PDF; wrappers use flex:1/minHeight:0 not height:100%.
Fix - IframePreview:
- Accept title + originalUrl props; show originalUrl in toolbar (falls
back to artifact src only when original_url absent); show title above
URL when available
- flex:1 + minHeight:0 instead of height:100% on the wrap div
- Single unified layout for page + pdf (both just show the iframe)
