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/tasks/routes.py

@@ -8,6 +8,7 @@ from fastapi import APIRouter, Depends, HTTPException, Query, Response, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.core.db import get_db
+from app.core.visibility import apply_visibility_filter
 from app.deps import get_current_user, require_permission
 from app.plugins.builtins.tasks import services
 from app.plugins.builtins.tasks.schemas import (
@@ -43,12 +44,15 @@ async def list_tasks(
 ):
     """List tasks with filtering and pagination."""
     tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    is_system_admin = current_user.get("is_system_admin", False)
     return await services.list_tasks(
         db, tenant_id,
         page=page, page_size=page_size,
         status=status, priority=priority,
         assigned_to=assigned_to, contact_id=contact_id,
         search=search,
+        user_id=user_id, is_system_admin=is_system_admin,
     )