[Agentic DX] Rust acceleration roadmap (libtmux-rust prototype) #634

Context

Local directory libtmux-rust includes Rust-acceleration hooks (for example src/libtmux/_rust.py) alongside core APIs.

Goal

Define a safe acceleration path with clear fallback and compatibility guarantees.

Low-lift ideas

• Document FFI boundary, feature flags, and fallback-to-pure-python behavior.
• Add benchmark harness and baseline metrics to justify acceleration paths.
• Add parity tests to guarantee Rust and Python paths return equivalent results.

Medium-lift ideas

• Isolate acceleration backend behind explicit interface boundaries.
• Add structured trace/debug modes for cross-language troubleshooting.
• Add CI matrix coverage for accelerated and non-accelerated builds.

High-lift ideas

• Define stable accelerator plugin contract for future backends.
• Publish compatibility policy for native extensions across platforms/Python versions.

Done when

• Native path behavior is measurable and predictable.
• Fallback guarantees are explicit.
• Cross-language maintenance risk is reduced by contract tests.