fix: stabilize renderer state and lifecycle updates

Prevent stale history, account, diagnostics, and language updates from repainting newer state. Keep queue virtualization, panel sizing, telemetry, cancellation, and runtime timing consistent across rapid UI changes. Strengthen painted-frame and lifecycle regression coverage, and brand packaged Windows metadata with the product publisher.

main.js

@@ -1,7 +1,7 @@
 process.env.UV_THREADPOOL_SIZE = process.env.UV_THREADPOOL_SIZE || '8';
 const { monitorEventLoopDelay, PerformanceObserver } = require('perf_hooks');
 const { app, BrowserWindow, ipcMain, dialog, clipboard, nativeTheme, Tray, Menu, nativeImage } = require('electron');
-const { configureStartupRenderer, createStartupWindow } = require('./lib/startup-renderer');
+const { configureStartupRenderer, createStartupWindow, resolveStartupLanguage } = require('./lib/startup-renderer');
 configureStartupRenderer(app);
 nativeTheme.themeSource = 'dark';
 const path = require('path');
@@ -1441,7 +1441,8 @@ function createWindow() {
 
   mainWindow.webContents.setBackgroundThrottling(false);
 
-  mainWindow.webContents.on('did-start-loading', () => {
+  mainWindow.webContents.on('did-start-navigation', (_event, _url, isInPlace, isMainFrame) => {
+    if (isInPlace || !isMainFrame) return;
     closeHandshakeReady = false;
     restoreClosePreparation(closePreparationAttempt);
   });
@@ -1490,10 +1491,12 @@ function createWindow() {
     debugLog(`CHILD PROCESS GONE: type=${details.type} reason=${details.reason} exitCode=${details.exitCode}`);
   });
 
+  let startupLanguage = 'en';
+  try { startupLanguage = resolveStartupLanguage(configStore.load()); } catch {}
   startupWindow.load(path.join(__dirname, 'renderer', 'index.html'), (err) => {
     _writeCrashLog('LOAD FILE FAILED', err);
     debugLog(`LOAD FILE FAILED: ${err && err.stack ? err.stack : err}`);
-  });
+  }, { query: { language: startupLanguage } });
 }
 
 function createTray() {