Add an "All" scope to the person switcher, default once there's a family

A lone member (or a parent of exactly one child) still lands straight on
their own record and never sees the switcher, same as before. The moment
there's more than one managed person, an "All" chip appears first and is
selected by default -- Home's cards (hero, needs-your-answer, dues) now
aggregate across everyone in scope instead of just one person, and
Calendar's own "My schedule" default does the same for its agenda.

PersonScopeMixin gains ``scope_everyone`` (bool) and ``people_in_scope``
(the effective list to filter by, regardless of which mode is active) --
kept separate from Calendar's own, unrelated ``?scope=all`` toggle
("every club event" vs. this "every person I manage"). Every RSVP form
now names its target member explicitly (``member_id``) rather than
relying on the old implicit "whoever is currently scoped" fallback, which
stops working the moment "All" -- not one person -- is the default.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

mobile/mixins.py

@@ -21,14 +21,24 @@ class PersonScopeMixin(ClubScopedPublicMixin):
 
     ``?as=<member-id>`` re-scopes the current screen to one managed person,
     same as the design doc's horizontally-scrolling chip row -- it re-scopes in
-    place rather than navigating. Falls back to the account's own Member, then
-    to the first managed child (e.g. a parent with no Member record of their own).
+    place rather than navigating. ``?as=all`` (or, once there's more than one
+    managed person, no ``?as=`` at all) scopes to *every* managed person --
+    that's the default the moment there's actually something to aggregate; a
+    member on their own, or a parent of exactly one child, has nothing to
+    aggregate and just lands on that one record, same as before this existed.
+
+    Screens that only ever operate on one person at a time keep using
+    ``scope_person`` (``None`` in "everyone" mode); screens that can
+    meaningfully show several people at once (Home's cards, Calendar's own
+    "my schedule" listing) should use ``people_in_scope`` instead, which is
+    always the right list to filter by regardless of which mode is active.
     """
 
     def dispatch(self, request, *args, **kwargs):
         self.me = Member.objects.filter(user=request.user).first() if request.user.is_authenticated else None
         self.managed_people = self._managed_people(request)
-        self.scope_person = self._resolve_scope_person(request)
+        self.scope_everyone, self.scope_person = self._resolve_scope(request)
+        self.people_in_scope = self.managed_people if self.scope_everyone else ([self.scope_person] if self.scope_person else [])
         return super().dispatch(request, *args, **kwargs)
 
     def _managed_people(self, request):
@@ -44,13 +54,19 @@ class PersonScopeMixin(ClubScopedPublicMixin):
         )
         return [self.me, *children]
 
-    def _resolve_scope_person(self, request):
+    def _resolve_scope(self, request) -> tuple[bool, Member | None]:
+        """Returns ``(scope_everyone, scope_person)`` -- exactly one of the
+        two is ever meaningful at a time (the other is ``False``/``None``)."""
         requested_id = request.GET.get("as")
-        if requested_id:
+        if requested_id and requested_id != "all":
             for person in self.managed_people:
                 if str(person.pk) == requested_id:
-                    return person
-        return self.managed_people[0] if self.managed_people else None
+                    return False, person
+        if requested_id == "all":
+            return True, None
+        if len(self.managed_people) > 1:
+            return True, None
+        return False, (self.managed_people[0] if self.managed_people else None)
 
     def get_context_data(self, **kwargs):
         unread_notification_count = 0
@@ -61,6 +77,7 @@ class PersonScopeMixin(ClubScopedPublicMixin):
             me=self.me,
             managed_people=self.managed_people,
             scope_person=self.scope_person,
+            scope_everyone=self.scope_everyone,
             has_staff_access=self.me is not None and has_management_access(self.request.user, self.request.club),
             unread_notification_count=unread_notification_count,
             season=current_season(self.request.club),