fix: pass local_hostname to smtplib so EHLO is FQDN-shaped

Gitea runner pods don't set setHostnameAsFQDN, so socket.getfqdn() returns
the single-label pod name. Stalwart's reject-non-fqdn rule (mail.md
<smtp-from-k8s-pod>) refuses the EHLO before MAIL FROM. Pass an explicit
FQDN to keep the action self-contained.

scripts/send.py

@@ -307,8 +307,12 @@ def main() -> int:
     msg.set_content(text)
     msg.add_alternative(html, subtype="html")
 
+    # Force a FQDN-shaped EHLO. Runner pods don't set setHostnameAsFQDN, so
+    # socket.getfqdn() returns the single-label pod name and Stalwart's
+    # reject-non-fqdn rule trips before MAIL FROM. See k8s-manager skill
+    # mail.md <smtp-from-k8s-pod>.
     print(f"notify-email: sending {palette['key']} to {to_addr} via {smtp_host}:{smtp_port}", file=sys.stderr)
-    with smtplib.SMTP(smtp_host, smtp_port, timeout=15) as s:
+    with smtplib.SMTP(smtp_host, smtp_port, local_hostname="ci.fritzlab.net", timeout=15) as s:
         s.send_message(msg)
     print("notify-email: sent", file=sys.stderr)
     return 0