refactor: migrate to ES modules

package.json type=module, tsconfig module/moduleResolution=NodeNext,
target es2022, explicit .js on all relative imports. Center: jsonwebtoken
& bcryptjs switched to default imports (ESM/CJS interop). Verified:
builds, boots, full auth + plugin round-trip work under ESM.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/events/events.module.ts

@@ -1,5 +1,5 @@
 import { Global, Module } from '@nestjs/common';
-import { EventsService } from './events.service';
+import { EventsService } from './events.service.js';
 
 @Global()
 @Module({