Follow-up to 208638e. Code review surfaced a few real issues; this
commit addresses them.
- login.post.js now uses the new sendMagicLink util instead of
duplicating the jti/jwt/Resend/logActivity logic. Reduces 60 lines.
- sendMagicLink accepts an optional pre-loaded Member doc, skipping
the redundant findOne when the caller already has one. customer.post.js
passes the just-created/upgraded member, dropping signup from 3
Mongo round-trips to 1 (lookup is gone; jti burn remains).
- sendMagicLink now lowercases the email defensively so callers don't
have to remember.
- rateLimit.js: replaced an effectively-dead eviction line with a
probabilistic sweep (~1% of calls scan and evict keys whose newest
entry has aged out). Caps unbounded Map growth under random-key
spraying.
- reconcile-payments.post.js: 401/403/404 from Helcim now bails out
immediately instead of burning all 3 retry attempts; dry-run
summary filters via the same RECONCILABLE_STATUSES set as apply
mode so counts match.
- Deleted WHAT-comments and section banners per CLAUDE.md no-comment
rule. Kept genuine WHY-comments (validateBeforeSave rationale,
amount-IGNORED-for-tickets, sendConfirmation deliberately-omitted).
Tests: 758/760 passing (unchanged).