Coach mode: bench-attendance filter overhaul, squad player detail, add-staff

- Attendance sheet: "All"/"Goalies" chips replaced with "Responded" (the
  new default -- present/selected/maybe) and "Silent"; goalies are just
  another player for a practice, and neither silent nor declined members
  are expected to show up, so the default view skips both.
- Today's KPI header gains an "Out" tile alongside Squad/In/Silent.
- Squad screen: each roster row now opens a per-player detail sheet with
  season attendance stats, tap-to-call buttons (the player's own phone/
  emergency phone, plus each guardian's for a child), and -- for whoever
  manages the team -- the position/jersey/captaincy edit and a remove-
  from-roster action that used to be desktop-only.
- Staff section gets its own "Add" entry point, mirroring the roster's
  bulk-add flow with a shared position picker (StaffAssignment.position
  is required, unlike a roster spot's).

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

mobile/urls.py

@@ -26,11 +26,14 @@ urlpatterns = [
     # Coach mode (C1-C6).
     path("coach/", coach_views.CoachTodayView.as_view(), name="coach_today"),
     path("coach/squad/", coach_views.CoachSquadView.as_view(), name="coach_squad"),
+    path("coach/squad/<uuid:membership_pk>/", coach_views.CoachRosterMemberView.as_view(), name="coach_roster_member"),
+    path("coach/squad/<uuid:membership_pk>/remove/", coach_views.CoachRosterRemoveView.as_view(), name="coach_roster_remove"),
     path("coach/schedule/", coach_views.CoachScheduleView.as_view(), name="coach_schedule"),
     path("coach/attendance/<uuid:event_id>/", coach_views.CoachAttendanceView.as_view(), name="coach_attendance"),
     path("coach/events/new/", coach_views.CoachCreateEventView.as_view(), name="coach_create_event"),
     path("coach/news/new/", coach_views.CoachCreateNewsView.as_view(), name="coach_create_news"),
     path("coach/roster/add/", coach_views.CoachAddPlayerView.as_view(), name="coach_add_player"),
+    path("coach/staff/add/", coach_views.CoachAddStaffView.as_view(), name="coach_add_staff"),
     path("coach/lineup/<uuid:event_id>/", coach_views.CoachLineupView.as_view(), name="coach_lineup"),
     path("coach/lineup/<uuid:event_id>/publish/", coach_views.CoachLineupPublishView.as_view(), name="coach_lineup_publish"),
 ]