fix(S1): use dedicated blocklist zero-address error

[liobrasil]

Summary

Fixes #32

Aligns blocklist batch-add validation with operation intent by using a dedicated blocklist zero-address error instead of the allowlist-specific error.

Key points:

• batchAddToBlocklist() no longer reverts with allowlist-specific error naming
• Added dedicated CannotBlocklistZeroAddress error for clearer admin/operator diagnostics
• Added regression test to lock expected revert selector for zero-address blocklist inputs

Changes:

• Added CannotBlocklistZeroAddress custom error
• Updated batchAddToBlocklist() to revert with CannotBlocklistZeroAddress() on address(0)
• Added test_BatchAddToBlocklist_RevertZeroAddress()

Test plan

• env FOUNDRY_OFFLINE=true forge test --match-contract FlowYieldVaultsRequestsTest --threads 1

[claude]

PR Review: fix(S1): use dedicated blocklist zero-address error

Summary: This is a correct, minimal fix for a copy-paste bug where batchAddToBlocklist() was reverting with the allowlist-specific CannotAllowlistZeroAddress error instead of a blocklist-appropriate one.

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Correctness

The bug is real and the fix is right. batchAddToBlocklist() was clearly scaffolded from batchAddToAllowlist() and the error wasn't updated, causing misleading revert messages for operators/admins. The one-line change at solidity/src/FlowYieldVaultsRequests.sol:595 is exactly the right fix.

Code Quality

• The new CannotBlocklistZeroAddress error follows the same NatSpec and naming conventions as the existing CannotAllowlistZeroAddress error.
• Placement in the error block (immediately after its allowlist counterpart) is logical.
• No unrelated changes — the diff is appropriately scoped.

Test Coverage

The new test test_BatchAddToBlocklist_RevertZeroAddress is correct:

• Uses vm.prank(c.owner()) appropriately, matching the onlyOwner modifier on batchAddToBlocklist.
• Verifies the exact error selector (.selector), which locks the ABI-level interface against future regressions — consistent with how similar tests in this file are written (e.g., test_CreateYieldVault_RevertZeroAmount).

One minor observation: there is no equivalent test_BatchAddToAllowlist_RevertZeroAddress test in the suite — the pre-existing CannotAllowlistZeroAddress path is untested at the unit level. That said, this is out of scope for this PR and should be tracked separately.

Security / Performance

No security or performance impact. This is purely a diagnostic fix — error naming only, no behavior change.

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Verdict: Looks good to merge. Clean fix, appropriate test, no concerns.