feat: email notifications with tabbed channel UI (v0.9.10)

Add email as a second notification channel alongside ntfy:
- Tabbed channel selector: ntfy | Email | Telegram (coming soon) | Discord (coming soon)
- Active channel shown with green status dot on tab
- Email tab: address input, Save & Enable, Test, Disable — same UX pattern as ntfy
- Backend: SMTP config in settings (SMTP_HOST/PORT/USER/PASSWORD/FROM/STARTTLS)
- Dispatcher: _send_email() helper wired into dispatch_notifications
- POST /api/notifications/test/email endpoint with descriptive error messages
- Email fires in same window as ntfy (respects quiet hours / digest hold)
- Telegram and Discord tabs show coming-soon banners with planned feature description
- .env.example documents all SMTP settings with provider examples

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/workers/notification_dispatcher.py

@@ -188,7 +188,17 @@ def dispatch_notifications(self):
                     logger.warning(f"ntfy dispatch failed for event {event.id}: {e}")
                     failed += 1
 
-            # Mark dispatched: ntfy was attempted, or user has no ntfy (RSS-only or neither)
+            email_enabled = prefs.get("email_enabled", False)
+            email_address = prefs.get("email_address", "").strip()
+            if email_enabled and email_address:
+                try:
+                    _send_email(event, email_address)
+                    sent += 1
+                except Exception as e:
+                    logger.warning(f"email dispatch failed for event {event.id}: {e}")
+                    failed += 1
+
+            # Mark dispatched: channels were attempted, or user has no channels configured (RSS-only)
             event.dispatched_at = now
             db.commit()
 
@@ -275,6 +285,52 @@ def _build_reason(payload: dict) -> str | None:
     return None
 
 
+def _send_email(event: NotificationEvent, email_address: str) -> None:
+    """Send a plain-text email notification via SMTP."""
+    import smtplib
+    from email.mime.text import MIMEText
+
+    from app.config import settings as app_settings
+
+    if not app_settings.SMTP_HOST or not email_address:
+        return
+
+    payload = event.payload or {}
+    bill_label = payload.get("bill_label", event.bill_id.upper())
+    bill_title = payload.get("bill_title", "")
+    event_label = _EVENT_TITLES.get(event.event_type, "Bill Update")
+
+    subject = f"PocketVeto: {event_label} — {bill_label}"
+
+    lines = [f"{event_label}: {bill_label}"]
+    if bill_title:
+        lines.append(bill_title)
+    if payload.get("brief_summary"):
+        lines.append("")
+        lines.append(payload["brief_summary"][:500])
+    reason = _build_reason(payload)
+    if reason:
+        lines.append("")
+        lines.append(reason)
+    if payload.get("bill_url"):
+        lines.append("")
+        lines.append(f"View bill: {payload['bill_url']}")
+    body = "\n".join(lines)
+
+    from_addr = app_settings.SMTP_FROM or app_settings.SMTP_USER
+    msg = MIMEText(body, "plain", "utf-8")
+    msg["Subject"] = subject
+    msg["From"] = from_addr
+    msg["To"] = email_address
+
+    with smtplib.SMTP(app_settings.SMTP_HOST, app_settings.SMTP_PORT, timeout=10) as s:
+        if app_settings.SMTP_STARTTLS:
+            s.starttls()
+        if app_settings.SMTP_USER:
+            s.login(app_settings.SMTP_USER, app_settings.SMTP_PASSWORD)
+        s.sendmail(from_addr, [email_address], msg.as_string())
+
+
 def _send_ntfy(
     event: NotificationEvent,
     topic_url: str,