feat: Enhance club payment claims and task automation

- Added `paid_amount_cents` column to `club_payment_claims` for better tracking of payments.
- Implemented compatibility checks for the new column in `clubPaymentClaimService` and `clubTaskAutomationService`.
- Updated various views to handle read-only states when editing is not allowed.
- Refactored forms in `ClubAccountsView`, `ClubInvoicesView`, `ClubTasksView`, and `ClubCommunicationView` to use factory functions for cleaner code.
- Introduced a new migration script to add the `paid_amount_cents` column if it doesn't exist and initialize it for existing paid claims.
- Created a detailed plan for enhancing club features and ensuring stability in existing modules.

backend/migrations/20260708_add_paid_amount_cents_to_club_payment_claims.sql

@@ -0,0 +1,36 @@
+-- club_payment_claims: Feld wie backend/models/ClubPaymentClaim.js (paidAmountCents)
+-- Fehlt in der DB -> SequelizeDatabaseError ER_BAD_FIELD_ERROR in Club-Dashboard,
+-- Aufgaben-Automation, Konten und Zahlungsforderungen.
+--
+-- Diese Migration ist idempotent:
+-- - fuegt `paid_amount_cents` nur hinzu, wenn die Spalte noch fehlt
+-- - initialisiert bestehende Datensaetze mit Status `paid` auf `amount_cents`
+-- Hinweis:
+-- Bereits teilweise bezahlte Altfaelle koennen ohne historische Buchungsdaten
+-- nicht exakt rekonstruiert werden und bleiben daher initial bei 0.
+
+SET @column_exists := (
+  SELECT COUNT(*)
+  FROM information_schema.COLUMNS
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'club_payment_claims'
+    AND COLUMN_NAME = 'paid_amount_cents'
+);
+
+SET @add_column_sql := IF(
+  @column_exists = 0,
+  'ALTER TABLE `club_payment_claims`
+     ADD COLUMN `paid_amount_cents` BIGINT NOT NULL DEFAULT 0
+       COMMENT ''Bereits bezahlter Anteil in Cent''
+       AFTER `amount_cents`',
+  'SELECT ''Column paid_amount_cents already exists'' AS message'
+);
+
+PREPARE add_column_stmt FROM @add_column_sql;
+EXECUTE add_column_stmt;
+DEALLOCATE PREPARE add_column_stmt;
+
+UPDATE `club_payment_claims`
+SET `paid_amount_cents` = `amount_cents`
+WHERE `status` = 'paid'
+  AND COALESCE(`paid_amount_cents`, 0) = 0;