chore: re-trigger SOP after memory-consultat typo fix

Add missing role="alert" and aria-live="assertive" to error state
banners in three components. WCAG 4.1.3 requires that status and error
messages be programmatically determinable via aria-live regions so
screen readers announce them immediately.

Changes:
- ChatTab.tsx: displayError banner — was missing role/aria-live
- ActivityTab.tsx: error banner — was missing role/aria-live
- AuditTrailPanel.tsx: error banner — had role="alert" but missing aria-live

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

canvas/src/components/AuditTrailPanel.tsx

@@ -172,6 +172,7 @@ export function AuditTrailPanel({ workspaceId }: Props) {
       {error && (
         <div
           role="alert"
+          aria-live="assertive"
           className="mx-4 mt-3 px-3 py-2 bg-red-950/30 border border-red-800/40 rounded text-xs text-bad shrink-0"
         >
           {error}

canvas/src/components/tabs/ActivityTab.tsx

@@ -189,7 +189,11 @@ export function ActivityTab({ workspaceId }: Props) {
         )}
 
         {error && (
-          <div className="px-3 py-1.5 bg-red-900/30 border border-red-800 rounded text-xs text-bad">
+          <div
+            role="alert"
+            aria-live="assertive"
+            className="px-3 py-1.5 bg-red-900/30 border border-red-800 rounded text-xs text-bad"
+          >
             {error}
           </div>
         )}

canvas/src/components/tabs/ChatTab.tsx

@@ -594,7 +594,11 @@ function MyChatPanel({ workspaceId, data }: Props) {
 
       {/* Error banner */}
       {displayError && (
-        <div className="px-3 py-2 bg-red-900/20 border-t border-red-800/30">
+        <div
+          role="alert"
+          aria-live="assertive"
+          className="px-3 py-2 bg-red-900/20 border-t border-red-800/30"
+        >
           <div className="flex items-center justify-between">
             <span className="text-[10px] text-red-300">{displayError}</span>
             {!isOnline && (