Serge flagged that PR #8's welcome-back template lost strategic
content (= the Paris depot address reminder, the IMPORTANT warning
against modifying it, and the 'Ravis de vous revoir' tone) by
substituting a more generic 'Vous \xc3\xaates d\xc3\xa9j\xc3\xa0 inscrit' template.
Restores the EXACT original EmailJS-era template now delivered
through Resend, with three minimal adaptations:
- Footer: '(c) 2025' \xe2\x86\x92 '(c) 2026'
- Logo URL: github.io \xe2\x86\x92 SITE_URL (= mva-globalfret.com)
- Paris address: now dynamic via PARIS_DEPOT_ADDRESS secret + {{ref}}
placeholder substitution (= each client sees their own MVA-XXX)
- Removed obsolete 'Email sent via EmailJS.com' tag (= now Resend)
Subject also reverted: 'Ravis de vous revoir, [firstname] !' instead
of the previously generic 'Vous \xc3\xaates d\xc3\xa9j\xc3\xa0 inscrit'.
Refs: post-cutover polish, fixes Issue 1.5 from Serge's E2E retest.
