feat: add ty type checking support and fix type issues

- Add ty.toml configuration with Django project root
- Add py.typed marker for type checking
- Fix type issues across codebase:
  - Add type ignore comments for redis.exceptions imports
  - Fix django.db.models.functions imports in utils
  - Fix getattr usage in accounts/forms
  - Remove unnecessary type annotations in dashboard/forms
- Configure ty to exclude migrations and respect ignore files
- All ty checks now pass (29 diagnostics -> 0)

dashboard_project/data_integration/management/commands/fix_datasource_schema.py

@@ -56,7 +56,8 @@ class Command(BaseCommand):
                         )
                     elif col == "sync_interval":
                         cursor.execute(
-                            "ALTER TABLE data_integration_externaldatasource ADD COLUMN sync_interval integer DEFAULT 3600"
+                            "ALTER TABLE data_integration_externaldatasource "
+                            "ADD COLUMN sync_interval integer DEFAULT 3600"
                         )
                     elif col == "timeout":
                         cursor.execute(

dashboard_project/data_integration/management/commands/test_redis.py

@@ -59,7 +59,7 @@ class Command(BaseCommand):
                 redis_client.delete(test_key)
             else:
                 self.stdout.write(self.style.ERROR("❌ Redis ping failed!"))
-        except redis.exceptions.ConnectionError as e:
+        except redis.exceptions.ConnectionError as e:  # type: ignore[attr-defined]
             self.stdout.write(self.style.ERROR(f"❌ Redis connection error: {e}"))
             self.stdout.write("Celery will use SQLite fallback if configured.")
         except ImportError: