Estimate PDF previews now load reliably with visual feedback

PDF iframe shows a loading indicator while rendering, cover fields are guaranteed when sending, and the preview page is clearly marked as editable.

Bug Fixes

The estimate preview page is now more reliable and transparent. The PDF iframe displays a Loading PDF… indicator while rendering, so you can see when it's working instead of encountering an unexplained "Not found" error. The page subtitle now reads Edit and Preview instead of just Preview, making it clear that you can edit the cover and summary fields right on this page.

Behind the scenes, we've added a safety net that guarantees cover-page text is populated before any estimate is sent to a client. If the AI-generated loss statement or summary narrative is missing, the system automatically regenerates it at send time — no more blank fields in sent PDFs.