fix: implement fork safety guard for native handles

[fr3on]

Description

Added automatic re-initialization logic to prevent double-free errors after pcntl_fork() when using multi-worker mode.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code

[github-actions]

🚀 Quill Performance Metrics

Environment: Ubuntu · PHP 8.3 · quill-core 0.0.2 · 2 workers Quill Core

Quill Binary Benchmark
  > Server     : Quill Core
  > Tool       : wrk
  > Duration   : 5s
  > Connections: 50
  > Workers    : 2
  > Starting Quill server...
  > Server is ready. Running benchmarks...
    Running 5s test @ http://127.0.0.1:8080/hello
      2 threads and 50 connections
      Thread Stats   Avg      Stdev     Max   +/- Stdev
        Latency     1.03ms    0.87ms   7.30ms   79.37%
        Req/Sec    25.98k     3.36k   35.01k    76.00%
      258922 requests in 5.01s, 40.00MB read
    Requests/sec:  51676.23
    Transfer/sec:      7.98MB

  > Benchmarks completed.