fix: music app improvements, desktop performance improvements

programs/src/desktop/apps/app_klog.cpp

@@ -145,6 +145,7 @@ static void klog_on_poll(Window* win) {
 
     klog->last_len = n;
     if (n > 0) klog->last_tail_byte = klog->klog_buf[n - 1];
+    win->dirty = true;
 }
 
 static void klog_on_close(Window* win) {

programs/src/desktop/apps/app_procmgr.cpp

@@ -54,6 +54,8 @@ static void procmgr_on_poll(Window* win) {
             }
         }
     }
+
+    win->dirty = true;
 }
 
 static void procmgr_on_draw(Window* win, Framebuffer& fb) {

programs/src/desktop/apps/app_terminal.cpp

@@ -311,12 +311,17 @@ static void terminal_on_poll(Window* win) {
         if (!terminal_poll(tts->tabs[i])) {
             // This tab's shell exited
             term_close_tab(tts, win, i);
+            win->dirty = true;
             // term_close_tab may have closed the window (last tab).
             // desktop_close_window calls on_close which nulls app_data
             // before the window slot is recycled, so win is still valid here.
             if (!win->app_data) return;
         }
     }
+
+    if (tts->tab_count > 0 && tts->tabs[tts->active_tab]->dirty) {
+        win->dirty = true;
+    }
 }
 
 // ============================================================================

programs/src/desktop/apps/apps_common.hpp

@@ -173,4 +173,4 @@ void open_reboot_dialog(DesktopState* ds);
 void open_wordprocessor(DesktopState* ds);
 void open_shutdown_dialog(DesktopState* ds);
 void open_sleep_dialog(DesktopState* ds);
-void desktop_poll_external_windows(DesktopState* ds);
+bool desktop_poll_external_windows(DesktopState* ds);