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/services/entity_permission_service.py

@@ -36,7 +36,6 @@ from app.models.sequence import Sequence
 from app.models.saved_filter import SavedFilter
 from app.models.saved_view import SavedView
 from app.models.webhook import Webhook
-from app.models.notification import Notification
 from app.models.custom_field_definition import CustomFieldDefinition
 from app.models.contact_folder import ContactFolder
 
@@ -56,20 +55,46 @@ ENTITY_MODELS: dict[str, type] = {
     "saved_filter": SavedFilter,
     "saved_view": SavedView,
     "webhook": Webhook,
-    "notification": Notification,
     "custom_field_definition": CustomFieldDefinition,
     "contact_folder": ContactFolder,
 }
 
-# Try to add plugin models if available
+# Core models with OwnedMixin (Phase 2 additions)
 try:
-    from app.plugins.builtins.dms.models import DmsFile
-    ENTITY_MODELS["dms_file"] = DmsFile
+    from app.models.entity_attachment import EntityAttachment
+    ENTITY_MODELS["entity_attachment"] = EntityAttachment
 except ImportError:
     pass
 try:
-    from app.plugins.builtins.calendar.models import CalendarEvent
-    ENTITY_MODELS["calendar_event"] = CalendarEvent
+    from app.models.entity_history import EntityHistory
+    ENTITY_MODELS["entity_history"] = EntityHistory
+except ImportError:
+    pass
+
+# Plugin models if available
+try:
+    from app.plugins.builtins.dms.models import File as DmsFile
+    ENTITY_MODELS["file"] = DmsFile
+except ImportError:
+    pass
+try:
+    from app.plugins.builtins.dms.models import Folder as DmsFolder
+    ENTITY_MODELS["folder"] = DmsFolder
+except ImportError:
+    pass
+try:
+    from app.plugins.builtins.calendar.models import CalendarEntry
+    ENTITY_MODELS["calendar_event"] = CalendarEntry
+except ImportError:
+    pass
+try:
+    from app.plugins.builtins.calendar.models import Calendar
+    ENTITY_MODELS["calendar"] = Calendar
+except ImportError:
+    pass
+try:
+    from app.plugins.builtins.calendar.models import Subtask
+    ENTITY_MODELS["subtask"] = Subtask
 except ImportError:
     pass
 try:
@@ -78,8 +103,8 @@ try:
 except ImportError:
     pass
 try:
-    from app.plugins.builtins.mail.models import Mailbox
-    ENTITY_MODELS["mailbox"] = Mailbox
+    from app.plugins.builtins.mail.models import MailAccount
+    ENTITY_MODELS["mailbox"] = MailAccount
 except ImportError:
     pass