test(rollback): fork-mode regression tests for precompile-storage checkpoint integration (BOP-214)

[amiecorso]

What

Adds three fork-mode regression tests verifying that mid-execution reverts in multi-write batch operations leave no orphan state.

File	Operation	Mid-batch revert trigger
test/unit/B20Security/batch/batchMint_rollback.t.sol	batchMint	Element 1 pushes totalSupply past supplyCap
test/unit/B20Security/batch/batchBurn_rollback.t.sol	batchBurn	Element 1's account has insufficient balance
test/unit/PolicyRegistry/createPolicyWithAccounts_rollback.t.sol	createPolicyWithAccounts	Batch length > MAX_BATCH_SIZE

Each test snapshots the relevant state (balances + totalSupply, or slot-level nextCounter + policy slot), triggers the revert, and asserts the post-revert state is byte-identical to pre-revert.

Why

Closes BOP-214. Companion to BOP-176 (Rust-side unit tests of the precompile-storage checkpoint mechanism in isolation).

Mock mode (revm-journaled storage) gives rollback for free — passing tests there mostly just confirms setup is correct and revm works. The signal is in fork mode, where the same tests exercise the real Rust precompile and verify that precompile-storage's JournaledState integration correctly rolls back partial writes on revert. A broken integration (writes that aren't journaled, checkpoints released early, future refactor that drops the hookup) would leave earlier writes persisted across the revert — this suite would catch it.

The createPolicyWithAccounts test is robust to either impl order:

• Solidity mock advances nextCounter + writes the policy slot before the batch check (BOP-207 tracks the reorder), relying on revm's journal to roll back.
• Rust precompile validates batch size first; no writes attempted.

Both reach the same end state (counter unchanged, predicted slot still zero); the test passes in both modes for different reasons today.

Verification

Mock mode:

forge test --match-contract 'Rollback' -vv
# 3 passed, 0 failed (256 fuzz runs each)

Fork mode (against live Rust precompile via patched anvil):

./script/run-fork-tests.sh --match-contract 'Rollback' -vv
# 3 passed, 0 failed (10 fuzz runs each)

Out of scope

Exhaustive coverage of every multi-write entrypoint — only enough to catch precompile-storage integration regressions. Comprehensive unit-level rollback coverage stays in BOP-176.

[linear]

BOP-214