SSR module: live progress bar for cache warming

The Cache warming row of the VITEC SSR module now shows a Bootstrap progress bar with a running counter instead of asking for a reload. New ajax route vitec_ssr_health (SsrController::healthJson) returns the node /__health JSON; ssr-warm-progress.js polls it every 2 s while a warm run is active and every 15 s otherwise (pauses in background tabs) and also refreshes the Cache: N pages / M MB line. The health fetch moved into SsrController::fetchHealth, shared by indexAction and the ajax route; its error text is English now. Verified live in the backend: bar, counter and cache line advance during a run.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

packages/vitec/Resources/Private/Templates/Ssr/Index.html

@@ -24,7 +24,7 @@
                             <span class="badge badge-success">running</span> {health.responseMs} ms<br>
                             Release <strong>{health.release.release}</strong>
                             (commit {health.release.commit})<br>
-                            Cache: {health.cachedPages} pages / {health.cacheMB} MB
+                            <span id="ssr-cache-line">Cache: {health.cachedPages} pages / {health.cacheMB} MB</span>
                         </f:then>
                         <f:else>
                             <span class="badge badge-danger">not reachable</span> {healthError}
@@ -34,13 +34,17 @@
             </tr>
             <tr>
                 <th>Cache warming</th>
-                <td>
+                <td id="ssr-warm-status" data-running="{f:if(condition: health.warming.running, then: '1', else: '0')}">
+                    <div class="progress" id="ssr-warm-progress" style="height:16px;margin-bottom:6px;{f:if(condition: health.warming.running, else: 'display:none')}">
+                        <div class="progress-bar progress-bar-striped progress-bar-animated bg-info" id="ssr-warm-bar" role="progressbar" style="width:0%;min-width:3em">0 %</div>
+                    </div>
+                    <div id="ssr-warm-text">
                     <f:if condition="{health.warming.running}">
                         <f:then>
                             <span class="badge badge-info">running</span>
                             {health.warming.done} of {health.warming.queued} pages rendered
                             ({health.warming.skipped} still fresh, {health.warming.failed} failed)
-                            <br><small>Reload this module to follow the progress.</small>
+                            <br><small class="text-muted">Live — updates every 2 seconds.</small>
                         </f:then>
                         <f:else>
                             <f:if condition="{health.warming.startedAt}">
@@ -57,6 +61,7 @@
                             </f:if>
                         </f:else>
                     </f:if>
+                    </div>
                 </td>
             </tr>
             <tr>