TestCloudContract drives the real handlers for every pad endpoint the
pad-cloud sidecar decodes (user-by-customer, plan, stripe-event-processed,
stripe-event-unmark, payment-failed, oauth-login, auth/me) and pins each
response's SHAPE (values replaced by type placeholders) in
testdata/cloud_contract/. pad-cloud keeps a copy and decodes each file
through its own client, so a key renamed or dropped on either side of
the repo boundary fails a test. The class this closes: user-by-customer
answered user_id while pad-cloud read id, so every subscription webhook
synced user "".
xarmian