feat: add bark battle browser prototype

src/games/bark-battle/domain/EnergyTugOfWar.ts

@@ -0,0 +1,20 @@
+export type AdvanceEnergyInput = {
+  energy: number;
+  playerPower: number;
+  opponentPower: number;
+  deltaMs: number;
+  balanceFactor: number;
+};
+
+export function advanceEnergy(input: AdvanceEnergyInput) {
+  const deltaSeconds = Math.max(0, input.deltaMs) / 1000;
+  const powerDelta = input.playerPower - input.opponentPower;
+  return clampEnergy(input.energy + powerDelta * input.balanceFactor * deltaSeconds);
+}
+
+export function clampEnergy(value: number) {
+  if (!Number.isFinite(value)) {
+    return 0;
+  }
+  return Math.min(100, Math.max(-100, value));
+}