[feature] Circuit Breaker

This contains 1/2 of the circuit breaker. The change here is that if we mint more than the max supply of rune, burn some rune from the reserve to restore the supply at 500m.

The second part is pausing opening of loans in this scenario.

Code Walkthrough https://www.youtube.com/watch?v=e6gZ77DdMrc

x/thorchain/keeper/v1/keeper.go

@@ -387,6 +387,32 @@ func (k KVStore) BurnFromModule(ctx cosmos.Context, module string, coin common.C
 }
 
 func (k KVStore) MintToModule(ctx cosmos.Context, module string, coin common.Coin) error {
+	version := k.GetVersion()
+	if version.GTE(semver.MustParse("1.109.0")) {
+		// circuit breaker
+		maxAmt, _ := k.GetMimir(ctx, "MaxRuneSupply")
+		if coin.Asset.IsRune() && maxAmt > 0 {
+			currentSupply := k.GetTotalSupply(ctx, common.RuneAsset())
+			surplus := common.SafeSub(currentSupply.Add(coin.Amount), cosmos.NewUint(uint64(maxAmt)))
+			if surplus.GT(cosmos.ZeroUint()) {
+				// Never mint an amount that would exceed MaxRuneSupply.
+				coin.Amount = common.SafeSub(coin.Amount, surplus)
+
+				reserveCoin := common.NewCoin(common.RuneAsset(), surplus)
+				if err := k.SendFromModuleToModule(ctx, ReserveName, module, common.NewCoins(reserveCoin)); err != nil {
+					// If unable to move the needed surplus coin from the Reserve, error out without any minting.
+					ctx.Logger().Error("fail to move coins during circuit breaker", "error", err)
+					return err
+				}
+			}
+		}
+
+		if coin.Amount.Equal(cosmos.ZeroUint()) {
+			// Don't proceed if the remaining amount to mint is zero.
+			return nil
+		}
+	}
+
 	coinToMint, err := coin.Native()
 	if err != nil {
 		return fmt.Errorf("fail to parse coins: %w", err)
@@ -397,34 +423,7 @@ func (k KVStore) MintToModule(ctx cosmos.Context, module string, coin common.Coi
 		return fmt.Errorf("fail to mint assets: %w", err)
 	}
 
-	version := k.GetVersion()
-	switch {
-	case version.GTE(semver.MustParse("1.109.0")):
-		// circuit breaker
-		coin := k.coinKeeper.GetSupply(ctx, common.RuneAsset().Native())
-		maxAmt, _ := k.GetMimir(ctx, "MaxRuneSupply")
-		if maxAmt > 0 && coin.Amount.GT(cosmos.NewInt(maxAmt)) {
-			diff := coin.Amount.SubRaw(maxAmt)
-			if diff.IsPositive() && diff.IsUint64() {
-				burn := common.NewCoin(common.RuneAsset(), cosmos.NewUint(diff.Uint64()))
-				if err := k.SendFromModuleToModule(ctx, ReserveName, ModuleName, common.NewCoins(burn)); err != nil {
-					ctx.Logger().Error("fail to move coins during circuit breaker", "error", err)
-					return err
-				}
-				err := k.BurnFromModule(ctx, ModuleName, burn)
-				if err != nil {
-					ctx.Logger().Error("fail to burn coins during circuit breaker", "error", err)
-					return err
-				}
-				burnEvt := NewEventMintBurn(BurnSupplyType, burn.Asset.Native(), burn.Amount, "circuit_breaker")
-				events, err := burnEvt.Events()
-				if err != nil {
-					return fmt.Errorf("fail to get events: %w", err)
-				}
-				ctx.EventManager().EmitEvents(events)
-			}
-		}
-	case version.GTE(semver.MustParse("1.95.0")):
+	if version.GTE(semver.MustParse("1.95.0")) {
 		// check if we've exceeded max rune supply cap. If we have, there could
 		// be an issue (infinite mint bug/exploit), or maybe runway rune
 		// hyperinflation. In any case, pause everything and allow the