Fleet now spawns the real zappier and middleware processes. Metered
timestamp/receipt/hash calls proxy to middleware when ZAPPIER_UPSTREAM
is set. CS credits, sales per-customer pricing, and QuickBooks export
are separate repos plugged into zappier-edge admin.
PDFs rewrite in-document .md/.html links to sibling PDFs. Catalog
start page is GETTING-STARTED (install, first-up, monitor). Billing
and user platform is zappier-edge (original ~/zappier tree).
