feat(admin): adaptive poll rate — 1 s active, 5 s idle after 15 s no traffic

Admin sandbox drill-down polls at 1 s when traffic is flowing (live label
updates feel instant), drops back to 5 s after 15 s of inactivity.
Chart bucket remains fixed at 5 s so x-axis labels stay correct; deltas
accumulate between buckets independently of poll rate.

Tier-dependent rate reserved for future sandbox-owner dashboard.

Co-Authored-By: Mira Rehfeld <noreply@anthropic.com>

apix-admin/src/main/resources/templates/DashboardResource/global.html

@@ -106,6 +106,6 @@ nav {
 <script>var __D = {statsJson.raw};</script>
 <script src="https://cdn.jsdelivr.net/npm/d3@7/dist/d3.min.js"></script>
 <script src="https://cdn.jsdelivr.net/npm/topojson-client@3/dist/topojson-client.min.js"></script>
-<script src="/admin.js?v=5"></script>
+<script src="/admin.js?v=6"></script>
 </body>
 </html>

apix-admin/src/main/resources/templates/DashboardResource/sandbox.html

@@ -151,6 +151,6 @@ button.promote:hover { background: #2ea043; }
 <script>var __D = {dataJson.raw};</script>
 <script src="https://cdn.jsdelivr.net/npm/d3@7/dist/d3.min.js"></script>
 <script src="https://cdn.jsdelivr.net/npm/topojson-client@3/dist/topojson-client.min.js"></script>
-<script src="/admin.js?v=5"></script>
+<script src="/admin.js?v=6"></script>
 </body>
 </html>