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/contact.py

@@ -13,6 +13,7 @@ from typing import Any
 
 from sqlalchemy import (
     Computed,
+    DateTime,
     Float,
     ForeignKey,
     Index,
@@ -39,6 +40,7 @@ class Contact(Base, TenantMixin, OwnedMixin):
     """
 
     __tablename__ = "contacts"
+    indexed_at: Mapped[Any] = mapped_column(DateTime(timezone=True), nullable=True)
     __table_args__ = (
         UniqueConstraint("tenant_id", "code", name="uq_contacts_tenant_code"),
         UniqueConstraint("tenant_id", "accounting_code", name="uq_contacts_tenant_accounting_code"),
@@ -191,7 +193,7 @@ class Contact(Base, TenantMixin, OwnedMixin):
     )
 
 
-class ContactPerson(Base, TenantMixin):
+class ContactPerson(Base, TenantMixin, OwnedMixin):
     """Ansprechpartner — 1:N child of a Contact.
 
     Represents a person working at / associated with a company contact.