PROXY protocol support

[martynp]

More detail to follow.

Based on rwf2/Rocket#2997

[Copilot]

Pull request overview

This PR adds optional PROXY protocol (v1/v2) support to the core listener stack, allowing Rocket to recover the original client address from a TCP-level preamble when running behind L4 proxies/load balancers (e.g., HAProxy TCP mode, AWS NLB), and documents/configures the feature across the project.

Changes:

• Introduces a new ProxyProtocolListener (behind the proxy-proto crate feature) and wires it into DefaultListener (including TLS composition).
• Adds a new proxy_protocol configuration key (env ROCKET_PROXY_PROTOCOL) plus user-facing docs and changelog entries.
• Adds testbench coverage and enables the feature in CI/test scripts.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
website/docs/11-deploying.md	Documents when/how to use PROXY protocol for client address recovery behind L4 proxies.
website/docs/10-configuration.md	Adds proxy_protocol config option and a new “PROXY Protocol” configuration section.
testbench/src/servers/sni_resolver.rs	Import reordering (no functional change).
testbench/src/servers/proxy_proto.rs	Adds integration tests validating forwarded remote address + rejection behavior.
testbench/src/servers/mod.rs	Registers the new proxy_proto test server module.
testbench/Cargo.toml	Enables rkt’s proxy-proto feature for testbench builds.
scripts/test.sh	Adds proxy-proto to the feature matrix exercised by tests.
core/lib/src/tls/listener.rs	Adjusts TlsListener’s Accept/connect plumbing to compose with additional listener layers.
core/lib/src/listener/proxy.rs	Implements PROXY protocol v1/v2 parsing + listener/stream wrapper (new).
core/lib/src/listener/mod.rs	Exposes the new listener::proxy module behind the proxy-proto feature.
core/lib/src/listener/default.rs	Wraps transport listeners with ProxyProtocolListener when compiled + adds config/error wiring.
core/lib/src/lib.rs	Documents the new proxy-proto crate feature.
core/lib/Cargo.toml	Declares the new proxy-proto feature flag.
CHANGELOG.md	Adds an Unreleased entry describing PROXY protocol support and configuration.

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[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated no new comments.