The preview modal's hardcoded sampleData had drifted from the templates'
declared variables arrays: it carried `password` and `expiration_date` and no
`host_name` at all, so {{host_name}}, {{gallery_password}} and {{expiry_date}}
rendered as literal placeholders in the gallery_created preview while
event_name/event_date/gallery_link substituted fine.
Derive the key set from the template's own `variables` instead, so nothing can
be missing again. editedTemplate already carries the array at the call site,
so no plumbing was needed. A small module-level lookup keeps sensible shapes
for the ~11 variables where shape matters (dates look like dates, links like
URLs), with a readable [name] fallback for anything uncurated -- curating all
~60 distinct variable names across the ~32 template seeds would just recreate
the drift trap.
Preview-only; real sent mail was never affected.
Refs testplan REPORT.md #17 (Part 3, J.04).
Paul Nothaft
1be27404fa