Lock governance withdrawals to voted proposal timelines

[AztecBot]

Summary

Governance withdrawals used the live configuration delay even after proposals had frozen longer voting and execution timing. This change records the latest vote-derived exit timestamp for each voter and clamps withdrawals so a timing-reduction proposal cannot let already-counted votes exit before the voted proposal reaches execution plus the existing buffer.

Fix

• Track a per-voter minimum exit timestamp when nonzero votes are cast.
• Clamp initiated withdrawals to the later of the live configuration delay and the vote-derived exit timestamp.
• Add a regression where a configuration update shortens timing while a later old-config proposal remains in flight.

Testing

• forge test --match-path test/governance/governance/scenarios/voteAndExitAfterConfigChange.t.sol -vvv
• forge test --match-contract 'InitiateWithdrawTest|VoteTest|NoVoteAndExitTest'
• git diff --check

Issues

• Closes AztecProtocol/aztec-claude#605 — Governance withdrawal delay uses live config, letting voters exit before frozen proposals execute

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Created by claudebox · group: l1-audit-remediation