Zoe's contribution question: does our portal preserve RNG state so a
simulation can continue in another process with the same random stream?
Answer today: no — no RNG existed. Answer now (Python + C): yes, bit-identical.
- New builtins: random-seed!, random, random-int, random-state, random-state!
- xoshiro256** (Blackman & Vigna 2018) — deterministic, portable, no libc rand
- State = 4 x u64; portal-v1 JSON gains 'rng' field with 8 x u32 halves
- Python and C produce bit-identical streams (verified: seed=42, 10 draws)
- Asm impl + cross-impl tests + whitepaper note: next commits
Ticket: docs/tickets/0001-portal-rng.md