- Add /admin/datafields (DatafieldsLive) for member and custom field config
- Remove Memberdata block from GlobalSettingsLive
- Router: drop /membership_fee_types, add new_fee_type and edit_fee_type under membership_fee_settings
- MembershipFeeSettingsLive: fee types table, collapsible examples; Index links updated
- PagePaths: admin_datafields, admin_import; remove membership_fee_types
- Sidebar: order and labels (Basic settings, Datafields, Membership fee settings, Import, Users, Roles)
- Gettext: German translations for sidebar and OIDC
- Tests: datafields and fee routes, permission and form tests updated
- Add oidc_* attributes to Setting, migration and Config helpers
- Secrets and OidcRoleSyncConfig read from Config (ENV overrides DB)
- GlobalSettingsLive: OIDC section with disabled fields when ENV set
- OIDC role sync tests use DataCase for DB access