Migrate var-dumper server to RoadRunner plugin

[butschster]

Migrates Var-Dumper server from RoadRunner TCP plugin with PHP worker pool to a dedicated native plugin with Jobs integration. This eliminates PHP workers for TCP handling, processes complete payloads in Go before pushing to Jobs, and significantly reduces resource consumption.

Motivation

The previous implementation used RoadRunner's generic TCP plugin, which had critical architectural issues:

Previous Architecture Problems

1. Dedicated Worker Pool for TCP: Required separate PHP workers just for handling TCP connections

   • Wasted server resources on workers that only forwarded data
   • Additional memory overhead (2 workers × 80MB = 160MB idle memory)
   • Workers blocked waiting for TCP data

2. Fragmented Payload Handling: TCP plugin streamed raw bytes to PHP workers

   • PHP had to manually buffer and reassemble fragmented TCP packets
   • Complex state management for incomplete messages
   • Risk of memory leaks from improper buffering
   • No guarantees about message boundaries

Why This Matters

Buggregator needs to handle hundreds of concurrent dumps during debugging sessions without impacting application performance. The old architecture wasted resources on TCP handling that could be better used for actual dump processing and UI serving.