Reviewer's follow-up: it's not enough to record when a user accepted
the Terms; we also need to record which version of the text they saw.
Changes:
- journal.users gains a nullable `terms_version` text column (nullable
so the three pre-existing users without a version are kept as-is).
- New apps/journal/app/lib/legal.ts exports TERMS_VERSION as a single
source of truth, reused by the legal pages' "Last updated" header
and by the registration flow as the value to send/store.
- Registration form posts `termsVersion` alongside `termsAccepted` on
all three relevant steps (start, finish, register-magic-link).
- API route validates that `termsVersion` is a non-empty string on
any step that requires terms, and forwards it to the auth server.
- auth.server finishRegistration and registerWithMagicLink now take
`termsVersion` and persist it on the users row.
- journal-auth spec gets a new scenario for version storage and a
rejection scenario for missing version.
PRIVACY_LAST_UPDATED is also exported from the same module and used
by the Privacy page header, keeping both pages on a single legal.ts
source of truth for "last updated" labels. Privacy is not per-user
stored — it's informational, not contract.
Existing users have NULL terms_version; if we ever prompt them to
re-accept updated Terms, we can backfill with the version they
re-accept at that point.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>