test: add constant accrual accounting invariants

[Schlagonia]

Summary

• add a constant accrual invariant handler with live profit/loss, queued report deltas, same-block accrual, unlock-time, fee, deposit, withdraw, redeem, and management sync actions
• assert latched assets, buffer accounting, supply conservation, handler accounting properties, and ERC4626 preview/max invariants
• add directed profit-locking edge cases around live losses, queued report losses/profits, and same-block accrual latching

Tests

• forge test --match-contract ConstantAccrualInvariantTest -vv
• forge test --match-path src/test/ProfitLocking.t.sol -vv
• forge test -vv