fix: stabilize the header on first paint

Pass the installed version with the startup language so the renderer can display it before asynchronous initialization.

Seed and start the upload sparkline immediately, keep a fixed update-action slot across all update states, and remove the delayed automatic update check.

Add first-frame regression coverage for version, speed baseline, update geometry, and startup query behavior.

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, resolveStartupLanguage } = require('./lib/startup-renderer');
+const { configureStartupRenderer, createStartupWindow, createStartupQuery } = require('./lib/startup-renderer');
 configureStartupRenderer(app);
 nativeTheme.themeSource = 'dark';
 const path = require('path');
@@ -1508,12 +1508,12 @@ function createWindow() {
     debugLog(`CHILD PROCESS GONE: type=${details.type} reason=${details.reason} exitCode=${details.exitCode}`);
   });
 
-  let startupLanguage = 'en';
-  try { startupLanguage = resolveStartupLanguage(configStore.load()); } catch {}
+  let startupQuery = createStartupQuery(null, app.getVersion());
+  try { startupQuery = createStartupQuery(configStore.load(), app.getVersion()); } 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 } });
+  }, { query: startupQuery });
 }
 
 function createTray() {
@@ -1652,7 +1652,7 @@ app.whenReady().then(async () => {
     }
   } catch {}
 
-  setTimeout(() => { void runAutomaticUpdateCheck(true); }, 3000);
+  void runAutomaticUpdateCheck(true);
   updateCheckInterval = setInterval(() => { void runAutomaticUpdateCheck(true); }, 5 * 60 * 1000);
   updateCheckInterval.unref?.();
 });