fix(sflr): revert on zero rate from sFLR contract

src/err/ErrFtso.sol

@@ -28,3 +28,6 @@ error InconsistentFtso();
 /// Thrown when decimals are too large to handle safely.
 /// @param decimals The decimals that were too large.
 error DecimalsTooLarge(uint256 decimals);
+
+/// Thrown when the sFLR contract returns a zero exchange rate.
+error ZeroSFLRRate();

src/generated/FlareFtsoWords.pointers.sol

@@ -10,7 +10,7 @@ pragma solidity ^0.8.25;
 // file needs the contract to exist so that it can be compiled.
 
 /// @dev Hash of the known bytecode.
-bytes32 constant BYTECODE_HASH = bytes32(0x96e4ec5ff213f69e32f76c5ce42fb5ae8a42af3ad080341ce1d1b74a0061723d);
+bytes32 constant BYTECODE_HASH = bytes32(0xa6e08b45005271ce77af0810fef0a97d7bbbdda007793e4be428ba5737caf303);
 
 /// @dev The hash of the meta that describes the contract.
 bytes32 constant DESCRIBED_BY_META_HASH = bytes32(0x8717d07737e3cedcdddea6cd3337ae762d7089918bf8d818fb0afc5b63e3985a);

src/lib/sflr/LibSceptreStakedFlare.sol

@@ -3,6 +3,7 @@
 pragma solidity ^0.8.19;
 
 import {IStakedFlr} from "../../interface/IStakedFlr.sol";
+import {ZeroSFLRRate} from "../../err/ErrFtso.sol";
 
 /// @dev Immutable upgradeable proxy contract to the sFLR contract.
 IStakedFlr constant SFLR_CONTRACT = IStakedFlr(address(0x12e605bc104e93B45e1aD99F9e555f659051c2BB));
@@ -13,6 +14,8 @@ library LibSceptreStakedFlare {
     /// according to the sFLR contract's current exchange rate.
     //forge-lint: disable-next-line(mixed-case-function)
     function getSFLRPerFLR18() internal view returns (uint256) {
-        return SFLR_CONTRACT.getSharesByPooledFlr(1e18);
+        uint256 rate = SFLR_CONTRACT.getSharesByPooledFlr(1e18);
+        if (rate == 0) revert ZeroSFLRRate();
+        return rate;
     }
 }

test/src/lib/sflr/LibSceptreStakedFlare.t.sol

@@ -4,7 +4,9 @@ pragma solidity =0.8.25;
 
 import {Test} from "forge-std-1.16.1/src/Test.sol";
 import {LibFork} from "test/fork/LibFork.sol";
-import {LibSceptreStakedFlare} from "src/lib/sflr/LibSceptreStakedFlare.sol";
+import {LibSceptreStakedFlare, SFLR_CONTRACT} from "src/lib/sflr/LibSceptreStakedFlare.sol";
+import {IStakedFlr} from "src/interface/IStakedFlr.sol";
+import {ZeroSFLRRate} from "src/err/ErrFtso.sol";
 
 uint256 constant BLOCK_NUMBER = 31843105;
 
@@ -13,8 +15,22 @@ contract LibSceptreStakedFlareTest is Test {
         vm.createSelectFork(LibFork.rpcUrlFlare(vm), BLOCK_NUMBER);
     }
 
+    function externalGetSFLRPerFLR18() external view returns (uint256) {
+        return LibSceptreStakedFlare.getSFLRPerFLR18();
+    }
+
     function testGetSFLRPerFLR18() external view {
         uint256 rate18 = LibSceptreStakedFlare.getSFLRPerFLR18();
         assertEq(rate18, 0.877817288626455057e18);
     }
+
+    function testGetSFLRPerFLR18ZeroReverts() external {
+        vm.mockCall(
+            address(SFLR_CONTRACT),
+            abi.encodeWithSelector(IStakedFlr.getSharesByPooledFlr.selector, uint256(1e18)),
+            abi.encode(uint256(0))
+        );
+        vm.expectRevert(abi.encodeWithSelector(ZeroSFLRRate.selector));
+        this.externalGetSFLRPerFLR18();
+    }
 }