fix: move ViewToggle into header bars and remove subtitle

Eliminates the dedicated ViewToggle row on CockpitPage by merging
it into IncidentHeader's action group via extraActions prop. Removes
subtitle from ViewToggle component entirely — the icon + label is
self-explanatory. Cleans up showSubtitle prop from all call sites.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/CockpitPage.tsx

@@ -255,7 +255,7 @@ export default function CockpitPage() {
           </button>
           <div className="flex-1" />
           {session.activeChatId && (
-            <ViewToggle currentView="cockpit" sessionId={session.activeChatId} showSubtitle={false} />
+            <ViewToggle currentView="cockpit" sessionId={session.activeChatId} />
           )}
           <button
             onClick={session.handleNewChat}
@@ -275,11 +275,12 @@ export default function CockpitPage() {
               onResolve={() => session.setShowConclude(true)}
               onStatusUpdate={session.messages.length >= 2 ? () => session.setShowStatusUpdate(true) : undefined}
               onClose={() => session.setShowConclude(true)}
+              extraActions={
+                <div className="hidden sm:block">
+                  <ViewToggle currentView="cockpit" sessionId={session.activeChatId} />
+                </div>
+              }
             />
-            {/* View toggle bar — desktop only (mobile has it in the header) */}
-            <div className="hidden sm:flex items-center justify-end px-4 py-1.5 border-b border-border/50">
-              <ViewToggle currentView="cockpit" sessionId={session.activeChatId} />
-            </div>
 
             {/* Resizable work zone + conversation log split */}
             <div ref={splitContainerRef} className="flex-1 flex flex-col min-h-0 relative">