Adds the single stochasticity source for the SOR measurement instrument so
every later stochastic decision (path selection R4, churn/selector R7, padding
jitter R4) is driven by one --sor-seed and is byte-reproducible run-to-run —
the R1 acceptance check and instrument-validation gate item 2.
- hh/src/sor/mod.rs: SplitMix64 + SHA-256 domain-separated sub-streams +
unbiased Lemire bounded sampling -> deterministic select_path/bringup.
Pure bookkeeping: no forwarder, no socket, no engine. Isolated-engine
containment assertions land with the R4 forwarder.
- hh/src/main.rs: `sor-bringup --sor-seed` emits the deterministic
circuit-build sequence as JSON (observable reproducibility).
- cmd_chat/sor/config.py: bit-for-bit Python mirror so the seed means the
same thing on both sides.
- Tests (Rust proptest+unit, Python pytest): SplitMix64 known-answer vector,
same-seed determinism, seed divergence, bounded/no-panic, and a shared
cross-language parity vector asserted identically in both suites.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
leetcrypt