Domain core: seeded RNG, asset registry, wallets, AMM pairs, mining

Pure logic layer with no game references: xoshiro128** RNG with savable
state, asset registry (PSC, CRC, CRT, CRA, SPARK, Ponero), wallets whose
taint and cost basis move with transfers, constant-product pools with
nightly reversion, and mining (Probidia/PMD GPUs, RatDigg ASICs, network
hash response, halving, wear and sudden death). 35 checks pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,9 @@
+bin/
+obj/
+*.user
+.vs/
+.idea/
+.vscode/
+*.swp
+.DS_Store
+tests/**/bin/