Handle failed direct debits through the same reminder mechanism

A Rücklastschrift is still the member's own failure to ensure cover or
provide valid bank details, so it belongs in the same escalation ladder
as a regular reminder -- it now occupies whatever level the claim is next
due for, alongside a "Rücklastschrift" preset next to the existing
Mahnstufe presets.

Mahnung vorbereiten no longer lets the board pick a level (it's computed
automatically from what's already been sent, since the sequencing was
already server-enforced) and replaces the single fee field with a small
items table (Beschreibung + Betrag), so a reminder can carry several
charges at once -- e.g. Rücklastschriftgebühr plus Bankgebühr plus Porto
-- each landing on the claim as its own line item instead of one lump
sum under a generic label. The description field offers the configured
standard texts but stays free-editable.

Those standard texts and amounts, plus the dunning levels themselves
(name/fee/deadline), are now configurable from Optionen -> Mahnungen
instead of only being editable by hand-editing repository.json, which
was the case for the whole reminder policy until now. Cleaned up
reminder_fee/failed_debit_fee on contribution rules while at it -- both
were unused leftovers superseded by this.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/ccma/services/documents.py

@@ -21,6 +21,7 @@ from ccma.domain.contributions import (
     claim_status,
     claim_total,
     money_text,
+    reminder_items_total,
 )
 from ccma.domain.dates import format_date_for_display
 from ccma.domain.models import MEMBERSHIP_STATUS_LABELS, Member
@@ -293,6 +294,10 @@ def _template_values(
         channel_labels = {"email": "E-Mail", "letter": "Brief", "personal": "Persönlich"}
         status = str(reminder.get("status", "draft"))
         channel = str(reminder.get("channel", ""))
+        reminder_items = reminder.get("items") or []
+        item_lines = [
+            f"{item.get('description', '')}: {item.get('amount', '0.00')} EUR" for item in reminder_items
+        ]
         values.update(
             {
                 "reminder.id": str(reminder.get("reminder_id", "")),
@@ -305,11 +310,19 @@ def _template_values(
                     str(reminder.get("payment_deadline") or "")
                 ),
                 "reminder.payment_deadline_days": str(reminder.get("payment_deadline_days", "")),
-                "reminder.fee": f"{reminder.get('fee', '0.00')} EUR",
+                "reminder.fee": f"{money_text(reminder_items_total(reminder))} EUR",
+                "reminder.items": "; ".join(item_lines),
                 "reminder.detail": str(reminder.get("detail", "")),
                 "reminder.channel": channel_labels.get(channel, channel),
             }
         )
+        repeats["reminder.items"] = [
+            {
+                "item.description": str(item.get("description", "")),
+                "item.amount": str(item.get("amount", "")),
+            }
+            for item in reminder_items
+        ]
     return values, repeats
 
 

src/ccma/services/reminder_mail.py

@@ -69,6 +69,15 @@ def reminder_mail_bytes(
     bic = str(organization.get("bic", "")).strip()
     payment_details = f"IBAN: {iban}" + (f"\nBIC: {bic}" if bic else "")
     detail = str(reminder.get("detail", "")).strip()
+    fee_items = reminder.get("items") or []
+    fee_lines = (
+        "\n".join(
+            f"{item.get('description', 'Gebühr')}: {item.get('amount', '0.00')} Euro"
+            for item in fee_items
+        )
+        if fee_items
+        else "Mahngebühr: 0.00 Euro"
+    )
     message.set_content(
         "\n".join(
             (
@@ -82,7 +91,7 @@ def reminder_mail_bytes(
                 f"{format_date_for_display(str(claim.get('due_date', '')))}",
                 f"Neue Zahlungsfrist: "
                 f"{format_date_for_display(str(reminder.get('payment_deadline', '')))}",
-                f"Mahngebühr: {reminder.get('fee', '0.00')} Euro",
+                fee_lines,
                 f"Hinweis: {detail}" if detail else "",
                 "",
                 "Bitte überweise den offenen Betrag unter Angabe deiner Mitgliedsnummer an:",