build_healthcare_campaigns.py had a divergent inline HTML generator (old teal-
header + yellow issue-box layout, missing the official-record card and the per-
segment verify-it-yourself blocks) that nobody called -- the live cron reads the
hand-tuned data/hc_campaigns/hc_*.html files directly. Removed the dead
generator + cmd_render(); render() now READS the canonical template file so the
files can't drift from a parallel generator. SEGMENTS is now a metadata registry
(subject, template, cta_path, price, list_name, campaign_name, selector) that the
multi-segment cron will consume. Verified --list and that send-test still reads
the real bodies.
