Add a Settings > Email previews page showing every branded email with sample data

Renders the real templates every send function uses (claim approved,
membership invoice, invoice reminder) against hand-built placeholder
context -- no real Member/ClubMembership/DuesInvoice row needed, so
nothing here can leak real data. Each card shows the subject line and
toggles between the HTML render (in an iframe, so the email's own
markup can't clash with the page's) and the plain-text body, using
the same bg-steel pill-toggle pattern as the news preview's NL/EN
switch (generalised to .view-toggle-btn, kept .news-lang-btn as an
alias). Admin-only, alongside Club identity in Settings.

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

management/views.py

@@ -52,6 +52,7 @@ from teams.models import Position, RefereeLevel, RefereeProfile, StaffAssignment
 from teams.services import eligible_roster_members
 
 from .bulk_import import build_member_import_template, parse_member_import_rows, read_member_import_workbook
+from .email_previews import EMAIL_PREVIEWS, render_preview
 from .forms import (
     AddChildForm,
     AddParentForm,
@@ -3320,6 +3321,21 @@ class ClubSettingsView(ClubAdminRequiredMixin, UpdateView):
         return super().get_context_data(**kwargs)
 
 
+class EmailPreviewListView(ClubAdminRequiredMixin, TemplateView):
+    """See email_previews.EMAIL_PREVIEWS's own docstring -- every branded email
+    this app can send, rendered against sample data for this club so an admin
+    can see exactly what a member/parent would receive without sending
+    anything. Same access level as Club identity: this is a branding/comms
+    concern, not day-to-day people/roster work."""
+
+    template_name = "management/email_previews.html"
+
+    def get_context_data(self, **kwargs):
+        club = self.request.club
+        previews = [{"key": preview.key, "label": preview.label, "description": preview.description, **render_preview(preview, club=club, request=self.request)} for preview in EMAIL_PREVIEWS]
+        return super().get_context_data(previews=previews, **kwargs)
+
+
 class OnboardingRequirementListView(MemberAdminRequiredMixin, ListView):
     """What a club requires from every member after they sign up or renew (a
     photo, a medical certificate, ...) -- see club/models.py's OnboardingRequirement