Registry API Refactoring (#144)

* Refactor core to use a flexible registry pattern

- Introduce a new registry mechanism for mailer providers
- Extract mailer provider enum to a separate file
- Implement dynamic mailer loading using a registry
- Update package dependencies and exports
- Improve modularity and extensibility of mailer implementation

* Refactor monitoring and billing services to use a flexible registry pattern

- Introduce a shared registry mechanism for dynamic service loading
- Replace static switch-based implementations with a registry-based approach
- Update instrumentation, CMS, and monitoring services to use the new registry
- Improve modularity and extensibility of service implementations
- Add Zod-based type-safe provider validation

* Simplify async registration in monitoring and billing services

- Remove unnecessary async wrappers for no-op registrations
- Update type definitions to support both async and sync registration functions
- Standardize registration approach for Paddle and Sentry providers

* Remove Tailwind package from packages where it is not being needed

* Remove Tailwind config references from pnpm-lock.yaml

* Update instrumentation registry to support dynamic monitoring providers

- Modify type definition to use NonNullable MonitoringProvider
- Import MonitoringProvider type from get-monitoring-provider
- Enhance type safety for instrumentation registration

packages/mailers/core/src/index.ts

@@ -1,37 +1,12 @@
-import { z } from 'zod';
-
-const MAILER_PROVIDER = z
-  .enum(['nodemailer', 'resend'])
-  .default('nodemailer')
-  .parse(process.env.MAILER_PROVIDER);
+import { MAILER_PROVIDER } from './provider-enum';
+import { mailerRegistry } from './registry';
 
 /**
- * @description Get the mailer based on the environment variable.
+ * @name getMailer
+ * @description Get the mailer based on the environment variable using the registry internally.
  */
-export async function getMailer() {
-  switch (MAILER_PROVIDER) {
-    case 'nodemailer':
-      return getNodemailer();
-
-    case 'resend': {
-      const { createResendMailer } = await import('@kit/resend');
-
-      return createResendMailer();
-    }
-
-    default:
-      throw new Error(`Invalid mailer: ${MAILER_PROVIDER as string}`);
-  }
+export function getMailer() {
+  return mailerRegistry.get(MAILER_PROVIDER);
 }
 
-async function getNodemailer() {
-  if (process.env.NEXT_RUNTIME === 'nodejs') {
-    const { createNodemailerService } = await import('@kit/nodemailer');
-
-    return createNodemailerService();
-  } else {
-    throw new Error(
-      'Nodemailer is not available on the edge runtime. Please use another mailer.',
-    );
-  }
-}
+export { MAILER_PROVIDER };