refactor: remove authentication module and integrate Better Auth

- Deleted the `autenticacao.ts` file to streamline the authentication process.
- Updated the `auth.ts` file to include new functions for user management and password updates.
- Modified the schema to enforce the presence of `authId` for users, ensuring integration with Better Auth.
- Refactored the seed process to create users with Better Auth integration, enhancing user management capabilities.
- Cleaned up the `usuarios.ts` file to utilize the new authentication functions and improve code clarity.

packages/backend/convex/schema.ts

@@ -381,8 +381,7 @@ export default defineSchema({
 
   // Sistema de Autenticação e Controle de Acesso
   usuarios: defineTable({
-    authId: v.optional(v.string()),
-    senhaHash: v.string(), // Senha criptografada com bcrypt
+    authId: v.string(),
     nome: v.string(),
     email: v.string(),
     funcionarioId: v.optional(v.id("funcionarios")),