mergeModuleHelpCatalogs now compares each per-module file's header
against the canonical schema and emits a one-shot prompts.log.warn per
module on drift, naming both the expected and actual header. Data
continues to load positionally so external modules built against the
old after/before schema still install cleanly — the warning is the
maintainer signal to rename their columns.
Centralize the canonical header in modules/module-help-schema.js so the
merger and the synthesizer (PluginResolver._buildSynthesizedHelpCsv)
read the same source of truth; future column renames are one edit.
Verified by installing all four bmad-org external modules
(bmb, cis, gds, tea) — every one ships the legacy after/before header
today and now fires an advisory warning while still merging cleanly
into _bmad/_config/bmad-help.csv with the canonical column names.
Alex Verkhovsky