📚 DOCS: Update README for v0.1.0 API changes

- Remove all outdated API examples (sendEmail, scheduleEmail)
- Add comprehensive examples using new payload.create() approach
- Include template engine configuration options (LiquidJS, Mustache, custom)
- Add detailed migration guide from v0.0.x to v0.1.0
- Update feature list to highlight type safety and Payload integration
- Replace old API methods section with helper functions
- Add template syntax reference for all supported engines
- Update Recent Changes section with v0.1.0 breaking changes

The README now accurately reflects the simplified collection-based API
and provides clear migration paths for existing users.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/payload-mailing",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "Template-based email system with scheduling and job processing for PayloadCMS",
   "type": "module",
   "main": "dist/index.js",