⚡ Bolt: Optimize LanguageProvider initialization

💡 What: Optimized `LanguageProvider` to use lazy state initialization for `language` and removed `isInitialized` state.
🎯 Why: The previous implementation triggered a second render on mount because it initialized state to 'de' and then updated it in a `useEffect`.
📊 Impact: Reduces initial render count of the entire application by 50% (from 2 to 1).
🔬 Measurement: Verified with `src/i18n/__tests__/initialRender.test.tsx` which confirms the render count is now 1.

Co-authored-by: ragusa-it <196988693+ragusa-it@users.noreply.github.com>

src/i18n/__tests__/initialRender.test.tsx

@@ -0,0 +1,36 @@
+// @vitest-environment jsdom
+import { render, act } from '@testing-library/react';
+import { LanguageProvider, useTranslation } from '../index';
+import { describe, it, expect } from 'vitest';
+
+describe('LanguageProvider Initial Render', () => {
+  it('should verify initial render count', async () => {
+    let renderCount = 0;
+
+    const Consumer = () => {
+      useTranslation();
+      renderCount++;
+      return null;
+    };
+
+    render(
+      <LanguageProvider>
+        <Consumer />
+      </LanguageProvider>
+    );
+
+    // Wait for any effects to run
+    await act(async () => {
+      await new Promise(resolve => setTimeout(resolve, 10));
+    });
+
+    // After optimization, renderCount should be 1.
+    // Previously it was 2.
+    expect(renderCount).toBe(1);
+
+    // Verify lang attribute is set (getInitialLanguage defaults to 'de' in jsdom if window undefined,
+    // but in jsdom window IS defined. navigator.language usually defaults to en-US in jsdom)
+    // We just check it's set to something valid ('en' or 'de')
+    expect(['en', 'de']).toContain(document.documentElement.lang);
+  });
+});