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/billing/gateway/src/server/services/billing-gateway/billing-gateway-registry.ts

@@ -0,0 +1,34 @@
+import 'server-only';
+
+import { z } from 'zod';
+
+import {
+  type BillingProviderSchema,
+  BillingStrategyProviderService,
+} from '@kit/billing';
+import { createRegistry } from '@kit/shared/registry';
+
+// Create a registry for billing strategy providers
+export const billingStrategyRegistry = createRegistry<
+  BillingStrategyProviderService,
+  z.infer<typeof BillingProviderSchema>
+>();
+
+// Register the Stripe billing strategy
+billingStrategyRegistry.register('stripe', async () => {
+  const { StripeBillingStrategyService } = await import('@kit/stripe');
+  return new StripeBillingStrategyService();
+});
+
+// Register the Lemon Squeezy billing strategy
+billingStrategyRegistry.register('lemon-squeezy', async () => {
+  const { LemonSqueezyBillingStrategyService } = await import(
+    '@kit/lemon-squeezy'
+  );
+  return new LemonSqueezyBillingStrategyService();
+});
+
+// Register Paddle billing strategy (not implemented yet)
+billingStrategyRegistry.register('paddle', () => {
+  throw new Error('Paddle is not supported yet');
+});