feat(email): SMTP fallback via OVH Zimbra + direct SMTP for @nordabiznes.pl

Domain nordabiznes.pl removed from M365 (moved to OVH Zimbra).
Graph API can no longer send as @nordabiznes.pl.

- Added _send_via_smtp() method using SMTP_HOST/SMTP_USER/SMTP_PASSWORD
- @nordabiznes.pl sender goes directly to SMTP (skips Graph API)
- Other domains still try Graph API first, SMTP as fallback
- .env updated with OVH Zimbra SMTP credentials

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

email_service.py

@@ -107,6 +107,12 @@ class EmailService:
         Returns:
             True if sent successfully, False otherwise
         """
+        # If sender is @nordabiznes.pl, go directly to SMTP (domain removed from M365)
+        sender = from_address or self.mail_from
+        if sender and '@nordabiznes.pl' in sender:
+            logger.info(f"Sender is @nordabiznes.pl — using SMTP directly (not Graph API)")
+            return self._send_via_smtp(subject, body_html or body_text, to, sender_name=sender_name, bcc=bcc)
+
         if not MSAL_AVAILABLE:
             logger.error("msal package not available - cannot send email")
             return False
@@ -159,7 +165,7 @@ class EmailService:
                 bcc_recipients = [{"emailAddress": {"address": email}} for email in bcc]
                 email_msg["message"]["bccRecipients"] = bcc_recipients
 
-            # Send email via Graph API
+            # Try Graph API first
             url = f"{self.graph_endpoint}/users/{sender}/sendMail"
             headers = {
                 "Authorization": f"Bearer {token}",
@@ -169,14 +175,62 @@ class EmailService:
             response = requests.post(url, headers=headers, json=email_msg, timeout=30)
 
             if response.status_code == 202:
-                logger.info(f"Email sent successfully to {to}")
+                logger.info(f"Email sent successfully via Graph API to {to}")
                 return True
             else:
-                logger.error(f"Failed to send email. Status: {response.status_code}, Response: {response.text}")
+                logger.error(f"Failed to send email via Graph API. Status: {response.status_code}, Response: {response.text}")
-                return False
+                # Fallback to SMTP if Graph API fails (e.g. domain removed from M365)
+                logger.info("Attempting SMTP fallback...")
+                return self._send_via_smtp(subject, body, to, sender_name=sender_name, bcc=bcc)
 
         except Exception as e:
-            logger.error(f"Exception during email sending: {e}", exc_info=True)
+            logger.error(f"Exception during Graph email sending: {e}", exc_info=True)
+            # Fallback to SMTP
+            logger.info("Attempting SMTP fallback after exception...")
+            return self._send_via_smtp(subject, body, to, sender_name=sender_name, bcc=bcc)
+
+    def _send_via_smtp(self, subject, body, to, sender_name=None, bcc=None):
+        """Fallback: send email via SMTP (OVH Zimbra)."""
+        import smtplib
+        from email.mime.text import MIMEText
+        from email.mime.multipart import MIMEMultipart
+        from email.utils import formataddr
+
+        smtp_host = os.getenv('SMTP_HOST', 'ssl0.ovh.net')
+        smtp_port = int(os.getenv('SMTP_PORT', '587'))
+        smtp_user = os.getenv('SMTP_USER', '')
+        smtp_pass = os.getenv('SMTP_PASSWORD', '')
+        mail_from = os.getenv('MAIL_FROM', smtp_user)
+        mail_from_name = sender_name or os.getenv('MAIL_FROM_NAME', 'NordaBiznes Portal')
+
+        if not smtp_user or not smtp_pass:
+            logger.error("SMTP fallback failed: SMTP_USER or SMTP_PASSWORD not configured")
+            return False
+
+        try:
+            msg = MIMEMultipart('alternative')
+            msg['Subject'] = subject
+            msg['From'] = formataddr((mail_from_name, mail_from))
+            msg['To'] = ', '.join(to) if isinstance(to, list) else to
+            if bcc:
+                msg['Bcc'] = ', '.join(bcc) if isinstance(bcc, list) else bcc
+
+            msg.attach(MIMEText(body, 'html', 'utf-8'))
+
+            all_recipients = list(to) if isinstance(to, list) else [to]
+            if bcc:
+                all_recipients.extend(bcc if isinstance(bcc, list) else [bcc])
+
+            with smtplib.SMTP(smtp_host, smtp_port, timeout=30) as server:
+                server.starttls()
+                server.login(smtp_user, smtp_pass)
+                server.sendmail(mail_from, all_recipients, msg.as_string())
+
+            logger.info(f"Email sent successfully via SMTP to {to}")
+            return True
+
+        except Exception as e:
+            logger.error(f"SMTP fallback failed: {e}", exc_info=True)
             return False