fix(ciphers): XORCipher now encrypts newline characters

[Ankur-Kataria]

Description

Fixes #308 — XORCipher was silently skipping newline (\n, \r, etc.) characters instead of encrypting them.

Root cause

The implementation used str.replace(/./g, ...). In JavaScript/TypeScript, the . metacharacter without the s (dotAll) flag does not match line-terminator characters (\n U+000A, \r U+000D, U+2028, U+2029). Those bytes were passed through unchanged, which is both a correctness bug and an information leak.

// Before — \n is silently passed through
str.replace(/./g, (char) => String.fromCharCode(char.charCodeAt(0) ^ key))

// After — Array.from iterates every character including line terminators
Array.from(str, (char) => String.fromCharCode(char.charCodeAt(0) ^ key)).join('')

What changed

File	Change
ciphers/xor_cipher.ts	Replace regex-based replacement with Array.from()
ciphers/test/xor_cipher.test.ts	Add two new test cases covering \n/\r and self-inverse property

Tests

All 3 tests pass (npm test -- --testPathPattern=xor_cipher):

• passing a string & number as an argument — existing case unchanged ✓
• encrypts newline and other line-terminator characters — new ✓
• XORCipher is its own inverse — new ✓