fix(migrations): merge main and rechain compliance migration as 031 after 030_add_mobile_devices

Merge main branch into compliance templates feature branch.

Main had advanced with migrations 027-030 (ensure_shared_links,
audit_logs, user_language_preference, mobile_devices) since this
branch forked. Our compliance migration was 027 with down_revision
026, which conflicted with main's 027_ensure_shared_links_table.

Changes:
- Merge main (including i18n, audit logs, mobile, GraphQL features)
- Resolve conflicts in app/api/__init__.py, app/models.py, tests/conftest.py
- Rename 027_add_compliance_templates → 031_add_compliance_templates
- Rechain: down_revision 026_add_scheduled_jobs → 030_add_mobile_devices
- Add ComplianceTemplate to migrations/env.py imports
- Alembic now has single head: 031_add_compliance_templates

migrations/env.py

@@ -20,13 +20,31 @@ from app.database import Base
 
 # Ensure all models are imported so Base.metadata is populated.
 from app.models import (  # noqa: F401
+    ApiToken,
     ApplicationSettings,
+    AuditLog,
+    BackupRecord,
+    ComplianceTemplate,
     DocumentMetadata,
     FileProcessingStep,
     FileRecord,
+    InAppNotification,
+    LocalUser,
+    MobileDevice,
+    Pipeline,
+    PipelineStep,
     ProcessingLog,
     SavedSearch,
+    ScheduledJob,
     SettingsAuditLog,
+    SharedLink,
+    SubscriptionPlan,
+    UserImapAccount,
+    UserIntegration,
+    UserNotificationPreference,
+    UserNotificationTarget,
+    UserProfile,
+    WebhookConfig,
 )
 
 # Alembic Config object – provides access to values in alembic.ini.