feat: multi-provider AI support with auto-detection

- Added support for Google Gemini, OpenAI, Anthropic, and Azure OpenAI
- Implemented API key validation with auto model detection
- Added Error Boundary for better error handling
- Migrated PDF generation to native jsPDF (better quality)
- Added PWA support with offline capabilities
- Implemented tests with Vitest
- Fixed language consistency (PT-BR)
- Improved accessibility (ARIA)

vitest.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vitest/config';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: './src/test/setup.ts',
+    include: ['src/**/*.{test,spec}.{js,ts,jsx,tsx}'],
+  },
+});