Refactor email handling for improved type safety and extensibility

- Replace `BaseEmailData` with `Email` type for stricter type validation
- Update `sendEmail` API to support new typed structure and template integration
- Migrate to `@xtr-dev/payload-mailing` for enhanced email sending capabilities
- Remove unnecessary null checks and redundant code in email scheduling logic
- Regenerate PayloadCMS types for aligning with revised schema changes
- Update dev scripts and imports for seamless compatibility with the new email module

dev/tsconfig.json

@@ -19,13 +19,13 @@
       "@payload-config": [
         "./payload.config.ts"
       ],
-      "temp-project": [
+      "@xtr-dev/payload-mailing": [
         "../src/index.ts"
       ],
-      "temp-project/client": [
+      "@xtr-dev/payload-mailing/client": [
         "../src/exports/client.ts"
       ],
-      "temp-project/rsc": [
+      "@xtr-dev/payload-mailing/rsc": [
         "../src/exports/rsc.ts"
       ]
     },