fix(webapp): address review feedback on env default region

- Scope RegionsPresenter env lookup to the resolved project (+ archivedAt: null)
  so a mismatched env id can't surface a default from another project.
- Index RuntimeEnvironment.defaultWorkerGroupId via a separate CONCURRENTLY
  migration to keep FK checks off a seq scan.

Author: myftija

apps/webapp/app/presenters/v3/RegionsPresenter.server.ts

@@ -74,7 +74,7 @@ export class RegionsPresenter extends BasePresenter {
     const environment = environmentId
       ? await this._replica.runtimeEnvironment.findFirst({
           select: { defaultWorkerGroupId: true },
-          where: { id: environmentId },
+          where: { id: environmentId, projectId: project.id, archivedAt: null },
         })
       : null;
 

internal-packages/database/prisma/migrations/20260609142055_add_environment_default_worker_group_index/migration.sql

@@ -0,0 +1,3 @@
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "RuntimeEnvironment_defaultWorkerGroupId_idx"
+  ON "public"."RuntimeEnvironment"("defaultWorkerGroupId");

internal-packages/database/prisma/schema.prisma

@@ -401,6 +401,7 @@ model RuntimeEnvironment {
   @@index([parentEnvironmentId])
   @@index([projectId])
   @@index([organizationId])
+  @@index([defaultWorkerGroupId])
 }
 
 /// Records of previously-valid API keys that are still accepted for authentication