Mixed resolver mode support

[Mygod]

No description provided.

[Copilot]

Pull request overview

This PR adds support for mixed resolver mode, allowing the client to simultaneously use both authoritative and recursive DNS resolvers with per-path congestion control and ACK delay settings.

Changes:

• Introduces RESOLVER_MODE environment variable for benchmarks with support for resolver, authoritative, and mixed modes
• Replaces connection-wide --authoritative flag with per-resolver --authoritative <IP:PORT> option
• Implements per-path congestion control selection (BBR for authoritative, DCUBIC for recursive)

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
vendor/picoquic	Updates picoquic submodule to support per-path mode and ACK delay
scripts/bench/run_rust_rust_10mb.sh	Adds mixed mode benchmark support with proxy infrastructure
scripts/README.md	Documents RESOLVER_MODE environment variable
docs/usage.md	Updates CLI documentation for per-resolver flags
docs/picoquic-changes.md	Documents per-path slipstream mode changes
docs/benchmarks.md	Adds mixed mode benchmark example
crates/slipstream-ffi/src/picoquic.rs	Adds FFI bindings for path callbacks and mode management
crates/slipstream-ffi/src/lib.rs	Defines ResolverMode enum and ResolverSpec struct
crates/slipstream-ffi/cc/slipstream_poll.c	Implements path lookup by address and unique ID
crates/slipstream-ffi/cc/slipstream_mixed_cc.c	Implements mixed-mode congestion control algorithm
crates/slipstream-ffi/build.rs	Builds new mixed CC source file
crates/slipstream-client/src/streams.rs	Tracks path events for dynamic path management
crates/slipstream-client/src/pacing.rs	Refactors pacing to use path quality instead of connection
crates/slipstream-client/src/main.rs	Implements resolver ordering and deduplication
crates/slipstream-client/src/dns.rs	Manages per-resolver state including modes and path IDs
crates/slipstream-client/src/client.rs	Orchestrates mixed-mode operation with per-path logic
README.md	Updates documentation for per-resolver authoritative flag
.github/workflows/ci.yml	Adds mixed mode benchmark to CI

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