fix: repair missing project brand kit column

app/projects/migrations/0015_repair_project_brand_kit_column.sql

@@ -0,0 +1,28 @@
+-- Repair projects.brand_kit_id when the brand-kit migration was only partially applied.
+-- Safe to re-run; preserves existing project rows and is intentionally forward-only.
+begin;
+
+alter table projects
+  add column if not exists brand_kit_id text;
+
+do $$
+begin
+  if not exists (
+    select 1
+    from pg_constraint
+    where conname = 'fk_projects_brand_kit'
+      and conrelid = 'projects'::regclass
+  ) then
+    alter table projects
+      add constraint fk_projects_brand_kit
+      foreign key (brand_kit_id)
+      references brand_kits(id)
+      on delete restrict;
+  end if;
+end
+$$;
+
+create index if not exists ix_projects_workspace_brand_kit
+  on projects(workspace_id, brand_kit_id);
+
+commit;