feat(config): expand config dump and address review (olivierlambert#112)

Follow-up to the config dump command addressing review feedback:

- Add top-level schema_version field
- Include disabled users: the enabled flag is part of the configuration,
  so a dump should show it rather than hide the row
- Drop operational sync state (last_synced, sync_token) from the
  caldav_sources section; add provider_type, auth_type, oauth2_provider
  and write_calendar_href
- Cover the relational config tables: accounts, availability_rules,
  availability_overrides, user_availability_rules, user_groups,
  event_type_calendars, event_type_member_weights, event_type_watchers,
  booking_frequency_limits, team_members, team_groups
- Extend auth, smtp and event_types sections to newer config columns
  (theme, captcha, meeting links, tls_mode, slot interval, cancel and
  reschedule notice, per-event-type timezone), still excluding all
  secrets (oidc_client_secret, captcha_secret, google_oauth2_client_secret,
  meeting_webhook_secret, password_enc, OAuth2 tokens, team invite_token)
- Add a dump_table helper to cut per-section query boilerplate
- rustfmt fix on the SMTP match block

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: olivierlambert