Fix/load medusa proj (#6639)

**What**
- Runs loadMedusaV2 when v2 flag is enabled.
- V2 loader loads only project-level framework features. E.g., project APIs, subscribers, jobs, and workflows.
- No plugin support yet.

packages/core-flows/src/index.ts

@@ -1,3 +1,4 @@
+export * from "./auth"
 export * from "./api-key"
 export * from "./customer"
 export * from "./customer-group"