style(visual-fidelity): pages-admin — batches B,C,F

- B: token-equivalent rgba → color-mix(srgb, var(--ember|green|candle) X%, transparent) so colors track dark mode
- C: drop stale var(--green, #...) fallbacks (canonical token now defined in main.css)
- F: inline circle badge → <CircleBadge/> in admin/index, members/[id], members/index

app/pages/admin/index.vue

@@ -65,7 +65,7 @@
                 <span class="item-sub">{{ member.email }}</span>
               </div>
               <div class="item-meta">
-                <span class="badge" :class="member.circle">{{ member.circle }}</span>
+                <CircleBadge :circle="member.circle" />
                 <span class="item-date">{{ formatDate(member.createdAt) }}</span>
               </div>
             </div>