Add defaultFromName config option and bump to v0.0.7

- Add defaultFromName to MailingPluginConfig interface
- Update MailingService to format from field with name when available
- Add getDefaultFrom() helper method for consistent formatting
- Format as "Name" <email@domain.com> when both name and email are provided
- Bump version to 0.0.7

🤖 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": "0.0.6",
+  "version": "0.0.7",
   "description": "Template-based email system with scheduling and job processing for PayloadCMS",
   "type": "module",
   "main": "dist/index.js",