refactor: remove core-events from main (scaffoldable via gen core-package events)

- Delete packages/core-events/ (15 files)
- Strip @repo/core-events from all 5 feature package.json + apps/web-next/package.json
- Strip @repo/core-events from apps/web-next/next.config.mjs transpilePackages
- Strip E1 + J no-restricted-syntax blocks from core-eslint/base.js (anchor remains)
- Update bind-production.ts: drop bus construction + IEventBus import; rename
  resolveEventsAndJobsProduction → resolveJobsProduction (queue only),
  resolveEventsAndJobsDevSeed → resolveJobsDevSeed (queue only);
  ctx no longer has bus field; BindProductionContext generic arg narrowed
- Update bind-production.test.ts: assert ctx.bus is undefined, drop
  PayloadJobsEventBus/InMemoryEventBus instanceof checks
- Update sign-up-welcome-email.test.ts: assert mailer stays empty without bus
- Inline userSignedUpEvent in auth (drop defineEvent import from core-events)
- Drop InMemoryEventBus fallback from auth/di/module.ts

Feature binders' bus?.subscribe/publish calls remain as no-ops. Scaffold
@repo/core-events back via: pnpm turbo gen core-package events

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/auth/src/events/user-signed-up.event.ts

@@ -1,6 +1,5 @@
 // packages/auth/src/events/user-signed-up.event.ts
 import { z } from "zod";
-import { defineEvent } from "@repo/core-events";
 
 export const userSignedUpEventSchema = z
   .object({
@@ -12,7 +11,9 @@ export const userSignedUpEventSchema = z
 
 export type UserSignedUpEvent = z.infer<typeof userSignedUpEventSchema>;
 
-export const userSignedUpEvent = defineEvent(
-  "auth.user.signed-up",
-  userSignedUpEventSchema,
-);
+// Inline event descriptor — core-events is optional. The shape { name, schema }
+// satisfies EventBusProtocol.publish / subscribe when the bus is present.
+export const userSignedUpEvent = {
+  name: "auth.user.signed-up" as const,
+  schema: userSignedUpEventSchema,
+};