refactor: simplify schema names and remove provider id columns

backend/scripts/migrate_provider_columns.sql

@@ -14,6 +14,70 @@ BEGIN
   END IF;
 END $$;
 
+-- companies.display_name -> companies.name
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = 'public' AND table_name = 'companies' AND column_name = 'display_name'
+  ) AND NOT EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = 'public' AND table_name = 'companies' AND column_name = 'name'
+  ) THEN
+    ALTER TABLE public.companies RENAME COLUMN display_name TO name;
+  END IF;
+END $$;
+
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = 'public' AND table_name = 'companies' AND column_name = 'legal_name'
+  ) THEN
+    ALTER TABLE public.companies DROP COLUMN legal_name;
+  END IF;
+END $$;
+
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = 'public' AND table_name = 'systems' AND column_name = 'provider_client_id'
+  ) THEN
+    ALTER TABLE public.systems DROP COLUMN provider_client_id;
+  END IF;
+END $$;
+
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.columns
+    WHERE table_schema = 'public' AND table_name = 'roles' AND column_name = 'provider_role_name'
+  ) THEN
+    ALTER TABLE public.roles DROP COLUMN provider_role_name;
+  END IF;
+END $$;
+
+DO $$
+BEGIN
+  IF EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema='public' AND table_name='roles' AND constraint_name='uq_roles_system_provider_role_name'
+  ) THEN
+    ALTER TABLE public.roles DROP CONSTRAINT uq_roles_system_provider_role_name;
+  END IF;
+END $$;
+
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM information_schema.table_constraints
+    WHERE table_schema='public' AND table_name='roles' AND constraint_name='uq_roles_system_name'
+  ) THEN
+    ALTER TABLE public.roles ADD CONSTRAINT uq_roles_system_name UNIQUE (system_id, name);
+  END IF;
+END $$;
+
 DO $$
 BEGIN
   IF EXISTS (