Step 6 of multi-instancing migration. HeadlessEngineEnv.EnsureInitialized
is split into EnsureProcessGlobals (idempotent, process-once) +
SeedCharaIdsOnCurrentAmbient (per-test). New TestBattleScope IDisposable
sets up a fresh BattleAmbientContext per test. NonParallelizable removed
from converted classes; assembly-level Parallelizable(Fixtures) enabled.
SVSim.BattleEngine.Tests fully green under parallel test execution.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Fold SetupCardEvent into a shared HeadlessEngineEnv.CreateHeadlessHandCard primitive
(consolidating the duplicated M2/M3 helpers), then add the M4 oracle: card 103111050
(ELF cost-1 1/1, when_play powerup add_offense=1&add_life=1 to target=self). New oracle
dimension = the played card's OWN stat delta (1/1 -> 2/2). Gate play_count>2 seeded via
the public AddCurrentTrunPlayCount; proven load-bearing (without the seed the fanfare
gates out and Atk stays 1). No new shim/data gaps were needed — only harness seeding.
Engine still 0 errors; check_drift clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
