feat: support PROXY protocol v1 and v2

[rustatian]

Summary

closes: roadrunner-server/roadrunner#937.

• Add independent http.proxy_protocol and http.ssl.proxy_protocol settings, with mandatory explicit trusted_proxies IPs/CIDRs and a 5s default header timeout.
• Require a PROXY header from trusted socket peers and drop every untrusted connection, including headerless traffic. Normalize scoped IPv6 socket addresses before IP matching.
• Use go-proxyproto v0.15.0 for v1/v2 parsing. Accept TCP4/TCP6 metadata and valid UNKNOWN/LOCAL headers; leave TLVs opaque rather than treating them as TLS or authentication state.
• Wrap raw listeners before HTTP or TLS processing, preserve existing request-address propagation, and close listeners on setup failures.
• Add schema/docs and wire-level, lifecycle, WebSocket, and PHP integration tests with self-contained TLS certificates.

Scope

HTTP/1.1, h2c, HTTPS HTTP/2, and existing Go-middleware WebSocket upgrades retain their behavior. Omitted sections leave their listeners unchanged. FastCGI, HTTP/3, and CertMagic's temporary ACME challenge listeners are not wrapped; the ACME-configured application HTTPS listener is supported.

The README documents strict health-check requirements, connection-wide identity, forwarding-header trust, v1 fragmentation behavior, and the parser's 4096-byte v2 payload limit. RoadRunner's dependency bump and bundled schema update can follow the HTTP module release.

[Copilot]

🔵 Needs a closer look

It introduces security-sensitive listener-wrapping and connection-admission behavior that warrants final human review despite tests and documentation updates.

Pull request overview

This PR adds first-class PROXY protocol v1/v2 support to the HTTP module by introducing explicit, per-listener configuration (plain HTTP vs HTTPS) and wrapping TCP listeners so client addresses can be derived from trusted PROXY headers before HTTP/TLS processing.

Changes:

• Introduces proxy_protocol configuration for plain HTTP and HTTPS (with required trusted_proxies and default 5s header read timeout) plus schema/README documentation.
• Adds a dedicated servers/proxyprotocol wrapper built on github.com/pires/go-proxyproto with validation and strict peer/header enforcement behavior.
• Adds unit + integration tests covering header parsing, timeouts, untrusted peers, HTTP/HTTPS behavior, WebSockets, and PHP REMOTE_ADDR propagation.

File summaries

File	Description
tests/proxy_protocol_test.go	End-to-end integration coverage (HTTP/HTTPS/h2c) verifying PROXY header behavior and address propagation.
tests/go.mod	Adds transitive module dependency bookkeeping for the test module.
tests/go.sum	Adds checksum entries for the new dependency in the test module.
servers/proxyprotocol/proxyprotocol.go	New PROXY protocol config + listener wrapper implementation and validation.
servers/proxyprotocol/proxyprotocol_test.go	Unit tests for config validation, header parsing/rewrites, timeouts, and trusted-peer enforcement.
servers/proxyprotocol/http_test.go	Behavior tests validating rejection semantics and compatibility with HTTP/TLS/WebSocket flows.
servers/https/https.go	Wraps the HTTPS listener with PROXY protocol support before ServeTLS and ensures listener closure on setup failures.
servers/https/https_test.go	Adds regression test ensuring listeners are closed on setup errors across proxy-protocol modes.
servers/https/config.go	Adds ssl.proxy_protocol config field and validates it against TLS/ACME enablement.
servers/https/config_test.go	Tests defaulting/validation for ssl.proxy_protocol, including default timeout behavior.
servers/http11/http.go	Wraps the plain HTTP listener with PROXY protocol support before serving.
schema.json	Adds proxy_protocol schema definitions and dependency constraints for plain HTTP + SSL.
README.md	Documents configuration, strict trust model, TLS ordering, and behavior notes/limits.
go.mod	Adds github.com/pires/go-proxyproto v0.15.0 dependency.
go.sum	Adds checksum entries for the new dependency.
config/config.go	Adds http.proxy_protocol to config and validates/initializes it during defaults init.

Review details

• Files reviewed: 14/16 changed files
• Comments generated: 1
• Review effort level: Lite

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[codecov]

Codecov Report

❌ Patch coverage is 96.96970% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.34%. Comparing base (4526a05) to head (deca8d5).

Files with missing lines	Patch %	Lines
servers/http11/http.go	93.33%	1 Missing ⚠️
servers/https/https.go	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #283      +/-   ##
==========================================
+ Coverage   87.61%   88.34%   +0.72%     
==========================================
  Files          28       29       +1     
  Lines        1292     1347      +55     
==========================================
+ Hits         1132     1190      +58     
+ Misses        160      157       -3     

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