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)

types/providers.ts

@@ -0,0 +1,42 @@
+export type AIProvider = 'gemini' | 'openai' | 'anthropic' | 'azure';
+
+export interface ProviderConfig {
+  id: AIProvider;
+  name: string;
+  description: string;
+  models: string[];
+  requiresEndpoint?: boolean;
+  defaultModel: string;
+}
+
+export const PROVIDERS: ProviderConfig[] = [
+  {
+    id: 'gemini',
+    name: 'Google Gemini',
+    description: 'Modelos avançados do Google com visão multimodal',
+    models: ['gemini-2.0-flash', 'gemini-2.5-flash', 'gemini-2.5-pro'],
+    defaultModel: 'gemini-2.5-flash'
+  },
+  {
+    id: 'openai',
+    name: 'OpenAI',
+    description: 'GPT-4 e modelos de visão da OpenAI',
+    models: ['gpt-4o', 'gpt-4o-mini', 'gpt-4-turbo', 'gpt-4-vision-preview'],
+    defaultModel: 'gpt-4o'
+  },
+  {
+    id: 'anthropic',
+    name: 'Anthropic (Claude)',
+    description: 'Claude 3 com análise avançada de documentos',
+    models: ['claude-3-opus-20240229', 'claude-3-sonnet-20240229', 'claude-3-haiku-20240307'],
+    defaultModel: 'claude-3-sonnet-20240229'
+  },
+  {
+    id: 'azure',
+    name: 'Azure OpenAI',
+    description: 'OpenAI via Azure com segurança enterprise',
+    models: ['gpt-4', 'gpt-4-32k', 'gpt-35-turbo'],
+    requiresEndpoint: true,
+    defaultModel: 'gpt-4'
+  }
+];