Update payment_records to 8.99 EUR gross, 0.44 EUR fees, 8.55 EUR net
payout to binky-hedgehog. Link member tegwick in membership ledger and
add Stripe reference catalog.
Replace pre-aggregated costs.json with expense_records.json (48 line-item
records) and payment_records.json. All monthly and cumulative totals are
computed deterministically in observatory/ledger.py. Correct Bubble.io to
$32/mo (since Feb 2025) — infrastructure €69.44/mo not €72.20.
