Add the management app: club-facing UI + real fee-payment tracking

Gives clubs a self-service /manage/ area for members, families, teams,
roles, and season memberships, alongside real fee-payment tracking
(FeePayment, record_payment/mark_as_paid/remaining_balance) so a
membership's paid status reflects actual money received instead of a
single manually-set flag.

club/services/fees.py

@@ -0,0 +1,69 @@
+"""Recording money received against a membership's fee.
+
+Mirrors billing.services.dues.record_payment for a different kind of money: a
+member's own club fee, not the club's platform subscription. amount_paid is kept in
+step here, never recomputed by re-aggregating FeePayment on every read.
+"""
+
+from decimal import Decimal
+
+from django.db.models import F
+from django.utils import timezone
+
+from club.models import ClubMembership, FeePayment
+
+
+def remaining_balance(membership):
+    return max(membership.fee_amount - membership.amount_paid, Decimal("0.00"))
+
+
+def record_payment(membership, *, amount, method=FeePayment.Method.BANK_TRANSFER, reference="", note="", recorded_by=None):
+    """Record money received against one membership's fee. Several payments may
+    land on one membership -- a family paying in two installments must not read as
+    unpaid. Updates amount_paid and re-syncs fee_status/status to match."""
+    payment = FeePayment.objects.create(membership=membership, amount=amount, method=method, reference=reference, note=note, recorded_by=recorded_by)
+
+    membership.amount_paid = F("amount_paid") + amount
+    membership.save(update_fields=["amount_paid"])
+    membership.refresh_from_db(fields=["amount_paid"])
+    _sync_fee_status(membership)
+
+    return payment
+
+
+def mark_as_paid(membership, *, recorded_by=None):
+    """The "settle this one" action behind both the per-row and bulk buttons. If
+    there's a real remaining balance, records it as a payment (auditable, shows up
+    in history); if fee_amount was never priced (remaining is 0), just flips the
+    flags directly -- there's no real transaction to log."""
+    remaining = remaining_balance(membership)
+    if remaining > 0:
+        record_payment(membership, amount=remaining, method=FeePayment.Method.OTHER, note="Marked as paid", recorded_by=recorded_by)
+    else:
+        _sync_fee_status(membership, force_paid=True)
+
+
+def _sync_fee_status(membership, *, force_paid=False):
+    if membership.fee_status == ClubMembership.FeeStatus.WAIVED:
+        return  # manual, independent of payments -- this never overrides it
+
+    if force_paid or (membership.fee_amount > 0 and membership.amount_paid >= membership.fee_amount):
+        new_status = ClubMembership.FeeStatus.PAID
+    elif membership.amount_paid > 0:
+        new_status = ClubMembership.FeeStatus.PARTIALLY_PAID
+    else:
+        new_status = ClubMembership.FeeStatus.UNPAID
+
+    membership.fee_status = new_status
+    update_fields = ["fee_status"]
+
+    # Same "become a full member" behavior the bulk action already had: settling
+    # the fee in full also activates the membership, once, first time only.
+    if new_status == ClubMembership.FeeStatus.PAID:
+        membership.status = ClubMembership.StatusChoices.ACTIVE
+        update_fields.append("status")
+        if membership.activated_at is None:
+            membership.activated_at = timezone.localdate()
+            update_fields.append("activated_at")
+
+    membership.save(update_fields=update_fields)