Release v0.6.3: fix capture banner ordering and check updates periodically

src/app.cpp

@@ -1254,8 +1254,9 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
                 if (MessageBoxW(hwnd, prompt.c_str(), L"KSwitcher Update", MB_YESNO | MB_ICONQUESTION) == IDYES)
                     app->checkUpdate(true, true, result->version);
             }
-            else
+            else if (app->notifiedUpdate != result->version)
             {
+                app->notifiedUpdate = result->version;
                 NOTIFYICONDATAW icon{sizeof(icon)};
                 icon.hWnd = hwnd; icon.uID = 1; icon.uFlags = NIF_INFO; icon.dwInfoFlags = NIIF_INFO;
                 wcscpy_s(icon.szInfoTitle, L"KSwitcher update available");
@@ -1274,7 +1275,7 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
         else if (result->interactive)
             MessageBoxW(hwnd, (L"Update failed.\n\n" + result->error).c_str(), L"KSwitcher Update", MB_OK | MB_ICONERROR);
         else
-            diagnosticEvent(L"Startup update check failed: " + result->error);
+            diagnosticEvent(L"Background update check failed: " + result->error);
         return 0;
     }
     case WM_HOTKEY:
@@ -1338,7 +1339,9 @@ LRESULT CALLBACK App::windowProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
     case WM_TIMER:
         if (wp == 5)
         {
-            KillTimer(hwnd, 5);
+            // After the initial 5-second check, repeat while the resident stays open.
+            // Rearm even when a check is already running or the previous one failed.
+            SetTimer(hwnd, 5, UpdateCheckIntervalMs, nullptr);
             app->checkUpdate(false);
             return 0;
         }