🇧🇷 Stringfy - Brazilian String Manipulation

The Rust library focused on Brazilian string operations with CPF/CNPJ validation and localized formatting.

🚀 Features

• ✅ Memory-optimized string operations (zero allocation when possible)
• ✅ CPF/CNPJ validation with Brazilian algorithms
• ✅ Brazilian formatting (phone, CEP, currency)
• ✅ Macro system for easy interpolation (br_format!)
• ✅ Unicode-safe and performant

📖 Usage

use stringer::*;

// String operations
let trimmed = trim("  hello  ");        // "hello"
let upper = upper("rust");              // "RUST"

// Brazilian validations
let valid = is_valid_cpf("111.444.777-35");  // true
let valid = is_valid_cnpj("11.222.333/0001-81"); // true

// Brazilian formatting  
let phone = format_phone_br("11987654321");     // "(11) 98765-4321"
let cep = format_cep("01234567");               // "01234-567"

// Macro system
let price = br_format!(currency, 150.50);      // "R$ 150.50"
let doc = br_format!(cpf, "11144477735");      // "111.444.777-35"