Phase 2: Visibility Filter & Owner ID

- Add OwnedMixin to 15 models (contact_folder, user_preference, workspace,
  mcp_server_config, agent_definition, automation_definition, report_template,
  report_instance, entity_link, comm_conversation, proactive_suggestion,
  ai_agent, ai_chat_session, tag, share_link)
- Migration 0102: Add owner_id column to 15 tables with backfill from user_id
- Fix EntityPermission Registry: remove notification, add entity_attachment,
  entity_history, subtask, calendar, folder; fix wrong class names
  (DmsFile→File, CalendarEvent→CalendarEntry, Mailbox→MailAccount)
- Add apply_visibility_filter to list endpoints in tags, tasks, mcp_client,
  automation, report_generator, ai_assistant routes
- Add owner_id to create handlers for all new OwnedMixin models
- Patch tasks/services.py and automation/services.py list methods with
  user_id and is_system_admin parameters

app/plugins/builtins/permissions/models.py

@@ -10,6 +10,7 @@ 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 Permission(Base, TenantMixin):
@@ -37,7 +38,7 @@ class Permission(Base, TenantMixin):
     access_level: Mapped[str] = mapped_column(String(10), nullable=False, default="read")
 
 
-class ShareLink(Base, TenantMixin):
+class ShareLink(Base, TenantMixin, OwnedMixin):
     """Public share link for a file — optional password and expiry."""
 
     __tablename__ = "share_links"