adding resend as net notification adapter

lib/notification/adapter/resend.md

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+### Resend Adapter
+
+Resend is a modern email delivery service that Fredy can use to send notifications.
+
+Setup:
+- Create a Resend account: https://resend.com/
+- Create an API key and add it to Fredy's configuration.
+- Choose the sender address (e.g., you@yourdomain.com). Verify the domain (https://resend.com/domains/) in Resend before using it.
+- Optional for local testing: you can use `onboarding@resend.dev`, but Resend may restrict who you can send to when using test domains.
+
+Multiple recipients:
+- Separate email addresses with commas (e.g., some@email.com, someOther@email.com).
+
+Notes & Troubleshooting:
+- Ensure the `from` address is verified or belongs to a verified domain in Resend.
+- If emails don't arrive, check your spam folder and Resend dashboard logs.
+- The template displays listing images via their public URLs; make sure images are reachable.