Separate guardians from members: a parent is not automatically a member

members/services/family.py enrolled a parent exactly like the child they were
registering, so every parent held a full membership: counted in the member
list, in the club and platform KPIs, and in the fee roll, with a fee record of
their own. ClubMembership.kind (member | guardian) separates the two.

A guardian is attached to the club only through their child. They hold the
login, can be contacted and can sit in a Group -- the stated exception -- but
they are not a member: no fee (clean() refuses one), absent from the member
list, the fee list and every member count, and not eligible for a roster or a
staff spot. A parent who also plays or coaches is a member who happens to be a
parent; the two facts are independent, which is why this is its own field
rather than inferred from FamilyMembership.role.

A field on ClubMembership rather than a separate model because everything that
answers "is this person attached to this club" already reads through that table
-- tenancy, groups, the club-wide event audience -- and a second kind of link
would need a parallel path through all of it. What changes is only who counts.

Two things that weren't obvious going in:

Excluding guardians had to be a subtraction, not a narrower filter. The obvious
move -- match only member-kind rows and drop the MEMBER-role branch, since an
active membership of any kind grants that role -- also hides someone the club
knows but hasn't signed up for a season yet, which is a real state the member
edit page supports. Two existing tests caught it. _guardians_only() subtracts
instead, so anyone who also plays, is on staff or runs the club stays visible.

Their tie to the club isn't seasonal but rides on a per-season row, so it has
to be carried forward or a parent silently drops off at the season boundary
while their child stays enrolled. Copied from the immediately preceding season
only, so a deliberate removal isn't resurrected from an older row.

The data migration reclassifies existing parents, deliberately skipping anyone
who plays, is on a team's staff or holds an elevated ClubRole -- demoting them
would strip them from their own team's roster eligibility. Anything ambiguous
stays a member, which an admin can flip; noticing someone quietly vanished is
much harder.

The import template gains a membership_kind column next to family_role (a
child marked guardian is refused), and the review screen shows what each row
will join as.

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

club/services/seasons.py

@@ -46,12 +46,39 @@ def generate_seasons(club, until):
         end = _season_end(start, club)
         season, was_created = Season.objects.get_or_create(club=club, start_date=start, end_date=end)
         if was_created:
+            _carry_guardians_into(club, season)
             created.append(season)
         start = end + datetime.timedelta(days=1)
 
     return created
 
 
+def _carry_guardians_into(club, season):
+    """Copy the previous season's guardians into a season that has just been created.
+
+    The other half of members.services.family.carry_guardians_forward, which
+    covers a guardian added *after* the later seasons already existed. Between
+    them a parent keeps their tie to the club across every season boundary --
+    without which they would quietly drop off the club while their child stayed
+    enrolled, which is exactly the state a guardian exists to prevent.
+
+    Copied from the immediately preceding season, not from "any season ever", so
+    a guardian an admin deliberately removed stays removed rather than being
+    resurrected from an older row.
+    """
+    from club.models import ClubMembership
+
+    previous = Season.objects.filter(club=club, start_date__lt=season.start_date).order_by("-start_date").first()
+    if previous is None:
+        return
+
+    guardians = ClubMembership.objects.filter(club=club, season=previous, kind=ClubMembership.Kind.GUARDIAN)
+    ClubMembership.objects.bulk_create(
+        [ClubMembership(club=club, member_id=guardian.member_id, season=season, kind=ClubMembership.Kind.GUARDIAN, status=guardian.status, signed_up_at=guardian.signed_up_at) for guardian in guardians],
+        ignore_conflicts=True,
+    )
+
+
 def _expected_season_dates(club, until):
     """The (start_date, end_date) pairs generate_seasons would produce for
     ``club`` from scratch, ignoring whatever already exists -- used by