fix(web_viewer): announce connection changes and let the log stream take focus

The navbar's connection text changed silently, so a screen-reader user wasn't told when the viewer lost or regained its link to the bot. It becomes a status region after the first update, which keeps the routine connect on every page load quiet and announces later changes; it's only rewritten when the text actually changes.

The Logs stream scrolls but couldn't take focus, so keyboard users couldn't scroll it. It is now a focusable region named "Bot log stream". It is deliberately not a live region: announcing every log line would drown everything else.

modules/web_viewer/templates/base.html

@@ -1277,8 +1277,13 @@
                 const statusElement = document.getElementById('connection-text');
                 const indicatorElement = document.getElementById('connection-status');
 
-                if (statusElement) {
+                if (statusElement && statusElement.textContent !== text) {
                     statusElement.textContent = text;
+                    // Announce later changes (a dropped or restored link), but
+                    // not the first connect every page load makes.
+                    if (!statusElement.hasAttribute('role')) {
+                        statusElement.setAttribute('role', 'status');
+                    }
                 }
                 if (indicatorElement) {
                     indicatorElement.className = `status-indicator status-${status}`;

modules/web_viewer/templates/logs.html

@@ -157,7 +157,7 @@
         </div>
     </div>
     <div class="card-body p-0">
-        <div id="log-container" class="log-container">
+        <div id="log-container" class="log-container" tabindex="0" role="region" aria-label="Bot log stream">
             <div class="text-muted py-3 text-center" id="log-placeholder">
                 <i class="fas fa-hourglass-half"></i> Waiting for log data…
             </div>