feat: auto-focus chat input on session switch and connection

src/App.tsx

@@ -86,7 +86,7 @@ export default function App() {
         <Header status={status} sessionKey={activeSession} onToggleSidebar={() => setSidebarOpen(!sidebarOpen)} activeSessionData={sessions.find(s => s.key === activeSession)} onLogout={logout} soundEnabled={soundEnabled} onToggleSound={toggleSound} />
         <ConnectionBanner status={status} />
         <Suspense fallback={<div className="flex-1 flex items-center justify-center text-zinc-500"><div className="animate-pulse text-sm">Loading…</div></div>}>
-          <Chat messages={messages} isGenerating={isGenerating} isLoadingHistory={isLoadingHistory} status={status} onSend={sendMessage} onAbort={abort} />
+          <Chat messages={messages} isGenerating={isGenerating} isLoadingHistory={isLoadingHistory} status={status} sessionKey={activeSession} onSend={sendMessage} onAbort={abort} />
         </Suspense>
       </div>
       <KeyboardShortcuts open={shortcutsOpen} onClose={() => setShortcutsOpen(false)} />