Added screen migration set device ID to null when device is deleted

Relaxes deleting of the screen when the associated device is deleted. Instead we set the `device_id` foreign key to `null` like we do for the `template_id` foreign key. This allows a screen to remain in case you want to repurpose it for another device.

Milestone: patch

config/db/migrate/20260805142625_alter_screen_device_id_constraint.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+ROM::SQL.migration do
+  up do
+    alter_table :screen do
+      drop_foreign_key [:device_id]
+      add_foreign_key [:device_id], :device, on_update: :cascade, on_delete: :set_null
+    end
+  end
+
+  down do
+    alter_table :screen do
+      drop_foreign_key [:device_id]
+      add_foreign_key [:device_id], :device, on_update: :cascade, on_delete: :cascade
+    end
+  end
+end

config/db/structure.sql

@@ -1654,7 +1654,7 @@ ALTER TABLE ONLY public.playlist_item
 --
 
 ALTER TABLE ONLY public.screen
-    ADD CONSTRAINT screen_device_id_fkey FOREIGN KEY (device_id) REFERENCES public.device(id) ON UPDATE CASCADE ON DELETE CASCADE;
+    ADD CONSTRAINT screen_device_id_fkey FOREIGN KEY (device_id) REFERENCES public.device(id) ON UPDATE CASCADE ON DELETE SET NULL;
 
 
 --
@@ -1805,4 +1805,5 @@ INSERT INTO schema_migrations (filename) VALUES
 ('20260630091508_add_device_log_level_column.rb'),
 ('20260714090149_add_device_api_key_column.rb'),
 ('20260721160734_add_device_command_column.rb'),
-('20260721160742_rename_device_log_function_columan_as_command.rb');
+('20260721160742_rename_device_log_function_columan_as_command.rb'),
+('20260805142625_alter_screen_device_id_constraint.rb');