refactor(dashboard): migrate member/dashboard to PageShell + ColumnsLayout

- Replace outer .dashboard wrapper with <PageShell>
- Replace <SidebarLayout> with <ColumnsLayout cols=events-sidebar :limit=5>
- Replace bespoke <div class=welcome> with <PageHeader> containing slotted meta
- Drop .dashboard and .welcome scoped CSS (flex chain + bespoke header)
- Update visual snapshots (welcome header now uses canonical PageHeader padding)

app/pages/member/dashboard.vue

@@ -1,5 +1,5 @@
 <template>
-  <div class="dashboard">
+  <PageShell>
     <ClientOnly>
       <!-- Loading State -->
       <div v-if="authPending" class="loading-state">
@@ -26,19 +26,18 @@
 
       <!-- Dashboard Content -->
       <template v-else>
-        <SidebarLayout :limit="5">
+        <ColumnsLayout cols="events-sidebar" :limit="5">
           <div class="dashboard-body">
             <!-- Member Status Banner -->
             <MemberStatusBanner />
 
             <!-- Welcome Header -->
-            <div class="welcome">
-              <h1>Welcome back, {{ memberData?.name }}</h1>
-              <div class="meta">
+            <PageHeader :title="`Welcome back, ${memberData?.name || ''}`">
+              <div class="dashboard-meta">
                 <CircleBadge :circle="memberData?.circle || 'community'" />
                 <span>${{ memberData?.contributionTier }} CAD/mo</span>
               </div>
-            </div>
+            </PageHeader>
 
             <!-- Upcoming Events + Quick Actions -->
             <div class="content-row">
@@ -204,7 +203,7 @@
               </div>
             </div>
           </div>
-        </SidebarLayout>
+        </ColumnsLayout>
       </template>
 
       <template #fallback>
@@ -214,7 +213,7 @@
         </div>
       </template>
     </ClientOnly>
-  </div>
+  </PageShell>
 </template>
 
 <script setup>
@@ -376,15 +375,6 @@ useHead({
 </script>
 
 <style scoped>
-/* ---- DASHBOARD LAYOUT ---- */
-.dashboard {
-  flex: 1;
-  display: flex;
-  flex-direction: column;
-  min-height: 0;
-  width: 100%;
-}
-
 /* ---- LOADING / UNAUTH STATES ---- */
 .loading-state {
   flex: 1;
@@ -451,30 +441,14 @@ useHead({
   margin-bottom: 20px;
 }
 
-/* ---- WELCOME HEADER ---- */
-.welcome {
-  padding: 28px 28px;
-  border-bottom: 1px dashed var(--border);
-  display: flex;
-  align-items: baseline;
-  gap: 16px;
-  flex-wrap: wrap;
-}
-
-.welcome h1 {
-  font-family: "Brygada 1918", serif;
-  font-size: 24px;
-  font-weight: 500;
-  color: var(--text-bright);
-  line-height: 1.2;
-}
-
-.welcome .meta {
+/* ---- WELCOME HEADER META ---- */
+.dashboard-meta {
   display: flex;
   align-items: baseline;
   gap: 12px;
   font-size: 12px;
   color: var(--text-dim);
+  margin-top: 8px;
 }
 
 .dashboard-body {
@@ -722,10 +696,6 @@ useHead({
     border-bottom: none;
   }
 
-  .welcome {
-    padding: 24px 20px;
-  }
-
   .content-block {
     padding: 20px;
   }