fix: deduplicate actions, promote ViewToggle tab bar, standardize naming

Remove duplicate Update/Close actions from chat toolbars (FlowPilotPage,
CockpitPage) — session lifecycle actions now live only in headers. Redesign
ViewToggle as a persistent tab bar with bottom-border active indicator and
ARIA attributes. Standardize all action naming: Resolve (emerald), Update
(blue), Close (rose), Pause (muted). Fix IncidentHeader Resolve from orange
to emerald. Delete unused FlowPilotActionBar component (227 lines). Update
ConcludeSessionModal copy to use forward-facing action verbs.

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

frontend/src/components/assistant/ViewToggle.tsx

@@ -18,6 +18,13 @@ interface ViewToggleProps {
   sessionId?: string
 }
 
+/**
+ * Persistent tab bar for switching between FlowPilot (chat) and Cockpit (triage) views.
+ * Renders as a horizontal tab strip with an active bottom-border indicator.
+ *
+ * NOTE: If the tab bar proves too tall or prominent in certain layouts,
+ * consider pivoting to a compact segmented control (Option A from the critique).
+ */
 export function ViewToggle({ currentView, sessionId }: ViewToggleProps) {
   const navigate = useNavigate()
   const hasCockpit = useFeatureFlag('flowpilot_cockpit')
@@ -37,19 +44,24 @@ export function ViewToggle({ currentView, sessionId }: ViewToggleProps) {
   }
 
   return (
-    <div className="flex items-center rounded-lg border border-border bg-card p-0.5 text-xs">
+    <div className="flex items-center border-b border-border px-3 shrink-0" role="tablist">
       {VIEW_OPTIONS.map(({ key, label, icon: Icon }) => (
         <button
           key={key}
+          role="tab"
+          aria-selected={currentView === key}
+          aria-current={currentView === key ? 'page' : undefined}
           onClick={() => handleSwitch(key)}
           className={cn(
-            'flex items-center gap-1.5 rounded-md px-2.5 py-1 font-medium transition-colors',
+            'flex items-center gap-1.5 px-3 py-2 text-xs font-medium border-b-2 -mb-px',
+            'transition-[color,border-color] duration-150',
+            'active:opacity-80',
             currentView === key
-              ? 'bg-elevated text-foreground'
-              : 'text-muted-foreground hover:text-foreground'
+              ? 'text-foreground border-primary'
+              : 'text-muted-foreground hover:text-foreground border-transparent'
           )}
         >
-          <Icon size={12} />
+          <Icon size={14} />
           {label}
         </button>
       ))}