AP3 manifest-emit service

Smaug compiles C/C++ into an MPC protocol and emits into the AP3 circuit manifest. This service exposes that toolchain over HTTP.

• /health — liveness
• /toolchain — resolved toolchain_ver + component SHAs
• /conformance — golden-vector hash conformance (live)
• /passes — LLVM version + pass-plugin load check
• /benchmarks — bundled programs
• /emit?program=psi — emit a manifest