Bytefray v4.0.0-alpha2 — Seeded Placement & Process Fairness

Bytefray v4.0.0-alpha2

Adds bytefray-rules-4-alpha2, a second v4 Ruleset identity differing from
bytefray-rules-4-alpha1 in exactly two gameplay semantics that the Phase 4
controlled gameplay study (~36,000 matches) identified as accidental rather
than designed.

What changed

• Seed-derived core placement. Entrant cores are placed from the match
  seed under a 64-cell minimum circular separation instead of a fixed
  evenly-spread seat layout, so own_core_base + arena_size / 2 is no
  longer a generally valid way to locate an opponent without observing
  anything. Derived from a SHA-256 counter stream, so placement is
  byte-identical across platforms and supported Python versions. Explicit
  --a-start/--b-start are still honoured exactly.
• Round-robin intra-entrant process selection. An entrant's own
  processes take action slots in rotation rather than always offering freed
  mid-tick quota to the earliest-declared eligible process. Quota
  allocation and redistribution are untouched: only which eligible
  process receives the next slot changes.

New agents hydra_alpha2 and nemesis_alpha2 acquire targets through the
Agent API v2 observation contract instead of the alpha1 placement
assumption; the historical hydra and Nemesis are unchanged.

What's unchanged

Agent API v2, replay schema 4, Q=8, core size, reach legality, the K=2
rotating entrant scheduler, disruption, and quota redistribution are all
unchanged. bytefray-rules-4-alpha1 remains available and explicitly
selectable everywhere a Ruleset can be named, for historical reproduction.
agents evaluate deliberately does not accept alpha2, since its placement
conditions are a disclosed evaluation-methodology axis that seeded
placement would contradict.

Known limitation

Global reach still provides whole-arena detection at no explicit cost, so
alpha2 removes the closed-form placement exploit but does not create a
reach economy. This is disclosed rather than treated as a last-minute
Ruleset change; it's the most likely subject of a future phase.

Compatibility

See docs/COMPATIBILITY.md,
docs/V4_ALPHA2_DESIGN.md,
and docs/V4_ALPHA2_PHASE5_QUALIFICATION.md
for the full contract, evidence, and release qualification record.

Packages

Package	Notes
Bytefray-Setup-4.0.0-alpha2.exe	Windows installer (admin, AMD64/x64)
bytefray-4.0.0-alpha2-windows.zip	Portable Windows onedir builds (all four executables)
bytefray-4.0.0a2-py3-none-any.whl	Pure Python 3.10-3.13 wheel
bytefray-4.0.0a2.tar.gz	Source distribution
SHA256SUMS.txt	Checksums for all of the above

This is a prerelease. We welcome gameplay feedback on the seeded placement
and process-fairness changes.