fix(display): cadence-aware contribution suffix across UI + admin dashboard

Add formatContribution helper in app/config/contributions.js and route
all member-facing and admin contribution displays through cadence-aware
expressions so annual members see /yr instead of /mo. Normalize annual
amounts to monthly equivalents in the admin dashboard revenue
aggregate now that contributionAmount is stored in cadence units.

app/pages/member/dashboard.vue

@@ -36,7 +36,7 @@
           <PageHeader :title="welcomeTitle">
             <div class="dashboard-meta">
               <CircleBadge :circle="memberData?.circle || 'community'" />
-              <span>${{ memberData?.contributionAmount ?? 0 }} CAD/mo</span>
+              <span>{{ formatContribution(memberData?.contributionAmount ?? 0, memberData?.billingCadence) }} CAD</span>
             </div>
             <p v-if="showSlackComingNote" class="slack-coming-note">
               Slack workspace access is part of your membership. Invitations are
@@ -171,7 +171,7 @@
               <div class="membership-row">
                 <span class="key">Contribution</span>
                 <span class="val"
-                  >${{ memberData?.contributionAmount ?? 0 }} CAD/month</span
+                  >{{ formatContribution(memberData?.contributionAmount ?? 0, memberData?.billingCadence) }} CAD</span
                 >
               </div>
               <div class="membership-row">
@@ -220,6 +220,8 @@
 </template>
 
 <script setup>
+import { formatContribution } from '~/config/contributions';
+
 useSiteMeta({ title: 'Dashboard', noindex: true });
 
 const { memberData, checkMemberStatus } = useAuth();