PDFs were classified as generic binary/text previews, rendering raw %PDF
bytes locally and failing entirely for remote-only files. Classify PDFs as
their own preview kind, load bytes through the existing local/remote
filesystem bridge, convert them to revocable Blob URLs for Chromium's
embedded viewer, migrate persisted pre-PDF tabs at restore, and retry
restored previews when the active filesystem connection changes.
Salvaged from #76008-era base onto current main: PDF classification now
composes with the remote-HTML enrichment branch, and the persisted-tab
migration runs before the One-Browser URL rekey in decodePreviewTabs.
Supersedes #76565.
Co-authored-by: Brooklyn Nicholson <brooklyn@brooklyn.sh>
Matt Prusak
c8fdc51740