feat(chain): ChainProfile registry for Smirk's 5 chains + centralize decimals

New src/chain/chainProfile.js — one data-driven source for chain params (decimals, mean block time, adapter family, URI scheme) across WOW/XMR/BTC/LTC/GRIN, all PoW/high-variance. inferCurrencyDecimals now delegates to it: WOW=11/XMR=12 unchanged, and BTC=8/LTC=8/GRIN=9 are fixed (were silently defaulting to 12). This is the seam the daemon/wallet/address adapters and the block-time difficulty-scaling plug into. +6 tests, suite 50/350 green.

P2 foundation on branch feat/credits-catalog-foundation.

src/chain/chainProfile.js

@@ -0,0 +1,76 @@
+/**
+ * ChainProfile registry — the 10× foundation stone for multi-chain (Pillar 3).
+ *
+ * A single, data-driven source for everything chain-specific that ISN'T an RPC call: money units
+ * (decimals / atomic divisor), the block-timing model (mean block time — which difficulty must
+ * scale to), the adapter family (which wallet/daemon adapter implements it), and the payment-URI
+ * scheme. The adapters (daemon/wallet clients, address validators) plug in per family and read
+ * their params from here.
+ *
+ * The set is exactly what the Smirk wallet supports — btc, ltc, xmr, wow, grin (see
+ * smirk-monorepo packages/core/src/types.ts AssetType) — all proof-of-work / high-variance, so the
+ * "a random block ends your run" mechanic is fair on every one. Adding a chain = one entry here
+ * plus a family adapter, never a fork.
+ */
+
+const DEFAULT_DECIMALS = 12;
+
+// family: 'monero' (subaddress + transfer_split), 'utxo' (BTC/LTC-style), 'mimblewimble' (Grin).
+const PROFILES = Object.freeze({
+    WOW:  Object.freeze({ id: 'WOW',  symbol: 'WOW',  decimals: 11, meanBlockTimeMs: 120000, family: 'monero',       uriScheme: 'wownero'  }),
+    XMR:  Object.freeze({ id: 'XMR',  symbol: 'XMR',  decimals: 12, meanBlockTimeMs: 120000, family: 'monero',       uriScheme: 'monero'   }),
+    BTC:  Object.freeze({ id: 'BTC',  symbol: 'BTC',  decimals: 8,  meanBlockTimeMs: 600000, family: 'utxo',         uriScheme: 'bitcoin'  }),
+    LTC:  Object.freeze({ id: 'LTC',  symbol: 'LTC',  decimals: 8,  meanBlockTimeMs: 150000, family: 'utxo',         uriScheme: 'litecoin' }),
+    GRIN: Object.freeze({ id: 'GRIN', symbol: 'GRIN', decimals: 9,  meanBlockTimeMs: 60000,  family: 'mimblewimble', uriScheme: 'grin'     })
+});
+
+function normalizeId(cryptoType) {
+    return String(cryptoType || '').trim().toUpperCase();
+}
+
+/**
+ * Resolve a chain profile. Unknown/unset falls back to a WOW-shaped default (11 decimals, ~2 min)
+ * so callers never crash on a mis-set CRYPTO_TYPE. Returns a frozen profile object.
+ */
+function getProfile(cryptoType) {
+    const id = normalizeId(cryptoType);
+    if (PROFILES[id]) return PROFILES[id];
+    return Object.freeze({ id: id || 'WOW', symbol: id || 'WOW', decimals: DEFAULT_DECIMALS, meanBlockTimeMs: 120000, family: 'monero', uriScheme: 'monero' });
+}
+
+function decimalsFor(cryptoType) {
+    return getProfile(cryptoType).decimals;
+}
+
+function meanBlockTimeMsFor(cryptoType) {
+    return getProfile(cryptoType).meanBlockTimeMs;
+}
+
+function familyFor(cryptoType) {
+    return getProfile(cryptoType).family;
+}
+
+function uriSchemeFor(cryptoType) {
+    return getProfile(cryptoType).uriScheme;
+}
+
+/** Atomic divisor as a BigInt (10 ** decimals) — safe for ETH-18-scale amounts (none here, but correct). */
+function atomicDivisor(cryptoType) {
+    return 10n ** BigInt(decimalsFor(cryptoType));
+}
+
+function isSupported(cryptoType) {
+    return !!PROFILES[normalizeId(cryptoType)];
+}
+
+module.exports = {
+    DEFAULT_DECIMALS,
+    PROFILES,
+    getProfile,
+    decimalsFor,
+    meanBlockTimeMsFor,
+    familyFor,
+    uriSchemeFor,
+    atomicDivisor,
+    isSupported
+};

src/game/helpers/gameModeUtils.js

@@ -1,3 +1,5 @@
+const ChainProfile = require('../../chain/chainProfile');
+
 const DEFAULT_DECIMALS = 12;
 
 const parseAtomicEnvValue = (val, fallback) => {
@@ -17,13 +19,9 @@ const parseAtomicEnvValue = (val, fallback) => {
     return Math.trunc(num);
 };
 
-const inferCurrencyDecimals = (symbol) => {
-    if (!symbol) return DEFAULT_DECIMALS;
-    const normalized = symbol.toUpperCase();
-    if (normalized === 'WOW') return 11;
-    if (normalized === 'XMR') return 12;
-    return DEFAULT_DECIMALS;
-};
+// Delegates to the ChainProfile registry — one source for all chains (WOW 11, XMR 12, BTC/LTC 8,
+// GRIN 9; unknown -> 12). Previously WOW/XMR were hardcoded and everything else silently got 12.
+const inferCurrencyDecimals = (symbol) => ChainProfile.decimalsFor(symbol);
 
 const getDecimalDivisor = (decimals = DEFAULT_DECIMALS) => {
     const normalized = Number.isFinite(decimals) ? decimals : DEFAULT_DECIMALS;