Enhance newsletter generation and dashboard functionality

- Introduce a new period selection feature in the dashboard for generating newsletters, allowing users to choose between "last month" and "last X days."
- Refactor newsletter generation logic to support filtering by article type (new, edited, or all) and improve the handling of filters in the dashboard.
- Update the dashboard template to include new input fields for period and article type, enhancing user experience.
- Improve CSS styles for send notifications and sections in the dashboard, providing clearer feedback on newsletter sending status.

app/services/smtp_sender.py

@@ -32,14 +32,16 @@ def send_newsletter(
     text_content: str,
     recipients: Sequence[str],
     scheduled: bool = False,
-) -> None:
+) -> tuple[str, str]:
     settings = get_smtp_settings(db)
     if settings["enabled"].lower() != "true":
-        _log(db, subject, recipients, "skipped", "SMTP ist deaktiviert.", scheduled)
-        return
+        detail = "SMTP ist deaktiviert. Bitte in der SMTP-Konfiguration aktivieren."
+        _log(db, subject, recipients, "skipped", detail, scheduled)
+        return "skipped", detail
     if not settings["host"] or not settings["from_email"] or not recipients:
-        _log(db, subject, recipients, "failed", "SMTP unvollständig konfiguriert.", scheduled)
-        return
+        detail = "SMTP unvollständig konfiguriert (Host, Absender oder Empfänger fehlen)."
+        _log(db, subject, recipients, "failed", detail, scheduled)
+        return "failed", detail
 
     msg = MIMEMultipart("alternative")
     msg.attach(MIMEText(text_content, "plain", "utf-8"))
@@ -56,9 +58,13 @@ def send_newsletter(
             if settings["username"]:
                 server.login(settings["username"], settings["password"])
             server.sendmail(settings["from_email"], list(recipients), msg.as_string())
-        _log(db, subject, recipients, "sent", "Versand erfolgreich.", scheduled)
+        detail = f"Versand erfolgreich an {len(recipients)} Empfänger."
+        _log(db, subject, recipients, "sent", detail, scheduled)
+        return "sent", detail
     except Exception as exc:
-        _log(db, subject, recipients, "failed", f"Versandfehler: {exc}", scheduled)
+        detail = f"Versandfehler: {exc}"
+        _log(db, subject, recipients, "failed", detail, scheduled)
+        return "failed", detail
 
 
 def run_scheduled_send_if_due(db: Session, subject: str, html_content: str, text_content: str) -> None: