refactor: wire normalized intent into activity UI

- ChatPane header now prefers session.currentIntent over the activity-
  derived label from summarizeSessionActivity for the busy status display
- TurnActivityPanel receives currentIntent via props and prefers it over
  extractLatestIntent (report_intent tool-call scanning) when the panel
  is active; falls back to tool-call scan for completed/inactive runs
- This replaces the report_intent-as-status inference pattern with the
  normalized assistant-intent event data from the backend

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/renderer/components/ChatPane.tsx

@@ -530,7 +530,7 @@ export function ChatPane({
               </div>
             )}
             {isSessionBusy && !pendingApproval && !pendingUserInput && (() => {
-              const label = summarizeSessionActivity(sessionActivity);
+              const label = session.currentIntent ?? summarizeSessionActivity(sessionActivity);
               return (
                 <div className="flex items-center gap-1.5 text-[12px] text-[var(--color-accent-sky)]">
                   <span className="size-2 animate-pulse rounded-full bg-[var(--color-accent-sky)]" />
@@ -593,6 +593,7 @@ export function ChatPane({
                         isActive={isTurnActive(item, itemIndex)}
                         turnStartedAt={item.turnStartedAt}
                         sessionId={session.id}
+                        currentIntent={session.currentIntent}
                         agentNames={item.agentNames}
                         isLastRunPanel={item.isLastRunPanel}
                         onDiscard={onDiscardRunChanges}

src/renderer/components/chat/TurnActivityPanel.tsx

@@ -41,6 +41,7 @@ export interface TurnActivityPanelProps {
   isActive: boolean;
   turnStartedAt?: string;
   sessionId: string;
+  currentIntent?: string;
   agentNames?: ReadonlySet<string>;
   isLastRunPanel?: boolean;
   onDiscard?: (sessionId: string, runId: string, files?: ProjectGitFileReference[]) => Promise<unknown>;
@@ -418,6 +419,7 @@ export function TurnActivityPanel({
   isActive,
   turnStartedAt,
   sessionId,
+  currentIntent,
   agentNames,
   isLastRunPanel,
   onDiscard,
@@ -471,8 +473,12 @@ export function TurnActivityPanel({
     return groupActivityStream(stream);
   }, [thinkingMessages, scopedEvents]);
 
-  // Extract intent text for the header
+  // Prefer the session-level normalized intent when active; fall back to
-  const intentText = useMemo(() => extractLatestIntent(scopedEvents), [scopedEvents]);
+  // scanning run timeline for report_intent tool calls (backward compat).
+  const intentText = useMemo(
+    () => (isActive ? currentIntent : undefined) ?? extractLatestIntent(scopedEvents),
+    [isActive, currentIntent, scopedEvents],
+  );
   const fallbackSummary = useMemo(
     () => !intentText ? generateActivitySummary(scopedEvents) : undefined,
     [intentText, scopedEvents],