feat: per-event organizer name + reply-to on ticket emails

Each organizer is different, so the sender identity of ticket emails is
now per event rather than per instance:

- `extra.organizer_name` → From display name "Organizer via <site title>"
  (site title alone when unset). The From address stays the instance
  mailbox — that is what DKIM signs — so this costs nothing in mail auth.
- `extra.reply_to_email` → Reply-To; blank falls back to the email on the
  LNbits account that owns the event wallet; no header when neither
  exists. When a reply-to exists the body says "Questions? Reply to this
  email and it reaches <organizer>", and "Organizer: <name>" is listed
  with the ticket details.

Both fields sit next to the existing per-event subject/body in the admin
dialog. The organizer's own wording (in whatever language) remains
`notification_body`.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EYwoAkZZmXMMmaBp4WGUBo

services.py

@@ -10,6 +10,8 @@ from email.mime.text import MIMEText
 from email.utils import formataddr, formatdate, make_msgid
 from html import escape
 
+from lnbits.core.crud import get_user
+from lnbits.core.crud.wallets import get_wallet
 from lnbits.core.models.users import UserNotifications
 from lnbits.core.services.nostr import send_nostr_dm
 from lnbits.core.services.notifications import send_user_notification
@@ -138,22 +140,38 @@ def _ticket_details(ticket: Ticket, event: Event) -> str:
         "or open the link above on your phone, and show the QR code at the "
         "door to be scanned in."
     )
+    if event.extra.organizer_name:
+        lines.append(f"Organizer: {event.extra.organizer_name}")
     return "\n".join(lines)
 
 
-def _ticket_delivery_message(ticket: Ticket, event: Event, base_message: str) -> str:
+def _ticket_details_with_reply_hint(
+    ticket: Ticket, event: Event, reply_to: str | None
+) -> str:
+    details = _ticket_details(ticket, event)
+    if reply_to:
+        who = event.extra.organizer_name or "the organizer"
+        details += f"\nQuestions? Reply to this email and it reaches {who}."
+    return details
+
+
+def _ticket_delivery_message(
+    ticket: Ticket, event: Event, base_message: str, reply_to: str | None = None
+) -> str:
     return (
-        f"{base_message}\n\n{_ticket_details(ticket, event)}"
+        f"{base_message}\n\n{_ticket_details_with_reply_hint(ticket, event, reply_to)}"
         f"\n\nTicket image: {_ticket_image_url(ticket)}"
     )
 
 
-def _ticket_email_html_message(ticket: Ticket, event: Event, base_message: str) -> str:
+def _ticket_email_html_message(
+    ticket: Ticket, event: Event, base_message: str, reply_to: str | None = None
+) -> str:
     """HTML twin of the text part. Deliberately no <img>: the card travels
     as an attachment (renders inline in most clients, works offline, and
     keeps SpamAssassin's HTML_IMAGE_ONLY rules quiet), and URLs become
     links."""
-    text_message = _ticket_delivery_message(ticket, event, base_message)
+    text_message = _ticket_delivery_message(ticket, event, base_message, reply_to)
     html = escape(text_message)
     html = re.sub(
         r"(https?://[^\s<]+)",
@@ -163,13 +181,41 @@ def _ticket_email_html_message(ticket: Ticket, event: Event, base_message: str)
     return f"<p>{html.replace(chr(10), '<br />')}</p>"
 
 
-def _ticket_notification_payload(ticket: Ticket, event: Event) -> tuple[str, str, str]:
+def _ticket_notification_payload(
+    ticket: Ticket, event: Event, reply_to: str | None = None
+) -> tuple[str, str, str]:
     subject, base_message = _ticket_notification_message(ticket, event)
-    text_message = _ticket_delivery_message(ticket, event, base_message)
-    html_message = _ticket_email_html_message(ticket, event, base_message)
+    text_message = _ticket_delivery_message(ticket, event, base_message, reply_to)
+    html_message = _ticket_email_html_message(ticket, event, base_message, reply_to)
     return subject, text_message, html_message
 
 
+async def organizer_reply_to(event: Event) -> str | None:
+    """Where replies to a ticket email should go: the event's explicit
+    `reply_to_email`, else the email on the LNbits account that owns the
+    event wallet, else nothing (no Reply-To header)."""
+    if event.extra.reply_to_email:
+        return str(event.extra.reply_to_email)
+    try:
+        wallet = await get_wallet(event.wallet)
+        if not wallet:
+            return None
+        user = await get_user(wallet.user)
+        email = (user.email or "").strip() if user else ""
+        return email if is_valid_email_address(email) else None
+    except Exception as exc:
+        logger.warning(f"Could not resolve organizer email for {event.id}: {exc}")
+        return None
+
+
+def organizer_sender_name(event: Event) -> str:
+    """From display name: "<organizer> via <site title>" when the event
+    names an organizer, else the site title."""
+    site = (settings.lnbits_site_title or "").strip() or "Tickets"
+    organizer = (event.extra.organizer_name or "").strip()
+    return f"{organizer} via {site}" if organizer else site
+
+
 async def _deliver_ticket_notifications(
     ticket: Ticket,
     event: Event,
@@ -180,7 +226,10 @@ async def _deliver_ticket_notifications(
     """Send the ticket by every configured channel and report per-channel
     outcome (upstream v1.6.8 shape). `email` / `nostr` override the event's
     opt-ins when not None; the instance-level prerequisites always apply."""
-    subject, text_message, html_message = _ticket_notification_payload(ticket, event)
+    reply_to = await organizer_reply_to(event)
+    subject, text_message, html_message = _ticket_notification_payload(
+        ticket, event, reply_to
+    )
     updated = False
 
     email_wanted = event.extra.email_notifications if email is None else email
@@ -220,6 +269,8 @@ async def _deliver_ticket_notifications(
                 attachments=[
                     (ticket_card_filename(ticket, event), image_png_bytes(card))
                 ],
+                reply_to=reply_to,
+                sender_name=organizer_sender_name(event),
             )
             ticket.extra.email_notification_sent = True
             result.email.sent = True
@@ -251,6 +302,8 @@ async def _send_ticket_email_notification(
     subject: str,
     html_message: str | None = None,
     attachments: list[tuple[str, bytes]] | None = None,
+    reply_to: str | None = None,
+    sender_name: str | None = None,
 ) -> None:
     """Multipart (text + HTML) ticket email through the instance SMTP
     settings. Core's `send_email_notification` is plain-text only, which is
@@ -269,7 +322,14 @@ async def _send_ticket_email_notification(
             raise ValueError(f"Invalid email address: {address}")
 
     msg = build_ticket_email(
-        from_email, to_emails, subject, message, html_message, attachments
+        from_email,
+        to_emails,
+        subject,
+        message,
+        html_message,
+        attachments,
+        reply_to=reply_to,
+        sender_name=sender_name,
     )
     username = settings.lnbits_email_notifications_username or from_email
     await asyncio.to_thread(
@@ -291,6 +351,8 @@ def build_ticket_email(
     message: str,
     html_message: str | None = None,
     attachments: list[tuple[str, bytes]] | None = None,
+    reply_to: str | None = None,
+    sender_name: str | None = None,
 ) -> MIMEMultipart:
     """Assemble the ticket email: text + HTML alternatives, PNG attachments
     (the ticket card), and the headers receivers score on — a Date and a
@@ -312,9 +374,13 @@ def build_ticket_email(
     else:
         msg = body
 
-    sender_name = (settings.lnbits_site_title or "").strip() or "Tickets"
-    msg["From"] = formataddr((sender_name, from_email))
+    display_name = (
+        sender_name or settings.lnbits_site_title or ""
+    ).strip() or "Tickets"
+    msg["From"] = formataddr((display_name, from_email))
     msg["To"] = ", ".join(to_emails)
+    if reply_to and is_valid_email_address(reply_to):
+        msg["Reply-To"] = reply_to
     msg["Subject"] = subject
     msg["Date"] = formatdate(localtime=True)
     msg["Message-ID"] = make_msgid(domain=from_email.rsplit("@", 1)[-1])