Add PHP library link

[otar]

Adds otar/jsonc - a production-ready PHP library for parsing JSONC format.

Features:

• Drop-in replacement for json_decode() with JSONC support
• Single-line (//) and multi-line (/* */) comments
• Trailing commas in objects and arrays
• Security hardening (BOM handling, null byte prevention, unclosed string detection)
• 100+ tests with 100% code coverage
• Zero dependencies (uses native PHP JSON extension)

Requirements: PHP 8.0+ (and JSON extension, enabled by default)

Installation: composer require otar/jsonc

Repository: https://github.com/otar/jsonc