feat(webapp): create new projects on the v2 engine

The engine column still defaults to V1 for historical rows, so a brand-new
project was transiently V1 until its first worker registration or deploy
upgraded it, and any trigger in that window hit the v3 upgrade error. New
projects are V2 up front. The V1 to V2 upgrade guards for existing legacy
projects are untouched.

Author: ericallam

apps/webapp/app/models/project.server.ts

@@ -101,6 +101,10 @@ export async function createProject(
       },
       externalRef: `proj_${externalRefGenerator()}`,
       version: version === "v3" ? "V3" : "V2",
+      // New projects run on the v2 engine. The Prisma column still defaults to V1
+      // for historical rows; the V1->V2 upgrade guards on worker-register / deploy
+      // stay in place to migrate existing legacy projects.
+      engine: "V2",
       onboardingData,
     },
     include: {