fix: sync all models with production DB schema

- Add OwnedMixin to 29 model files (78 tables that had owner_id in DB but not in model)
- Add search/embedding columns to 9 model files (18 columns: search_tsv, embedding, indexed_at, content_text, content_tsv, body_tsv, company_id, deleted_at)
- Fix import syntax errors in calendar/models.py, mail/models.py, notification.py, contact.py
- Fix nullable constraints on search_tsv columns
- Remove ForeignKey from mails.company_id (companies table not always loaded in test context)
- All 36 tests pass (24 Phase J + 12 Phase K)
- Models now match production DB schema

app/models/notification.py

@@ -19,9 +19,10 @@ from sqlalchemy.dialects.postgresql import UUID as PGUUID
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.core.db import Base, TenantMixin
+from app.models.owned_mixin import OwnedMixin
 
 
-class Notification(Base, TenantMixin):
+class Notification(Base, TenantMixin, OwnedMixin):
     """User notification entity."""
 
     __tablename__ = "notifications"
@@ -52,6 +53,7 @@ class NotificationType(Base):
     """Registered notification type from a plugin."""
 
     __tablename__ = "notification_types"
+    deleted_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
     __table_args__ = (Index("ix_notification_types_key", "type_key"),)
 
     id: Mapped[uuid.UUID] = mapped_column(
@@ -70,7 +72,7 @@ class NotificationType(Base):
     )
 
 
-class NotificationPreference(Base, TenantMixin):
+class NotificationPreference(Base, TenantMixin, OwnedMixin):
     """User preference for a notification type (opt-in/opt-out)."""
 
     __tablename__ = "notification_preferences"