fix(perps): enforce stale oracle gate on liquidation

[rndrntwrk]

Summary

This PR fixes the stale-oracle liquidation bypass in the EVM perps engines. Liquidation now uses the same max-oracle-delay gate as normal perps oracle sync instead of entering a special liquidation context that allowed stale-but-still-oracle-readable prices.

Security invariant

A liquidation must not execute from an oracle price older than the market engine maxOracleDelay, even if the underlying SkillOracle has a longer max delay.

Changes

• remove the liquidation-context stale-oracle bypass from AgentPerpEngine
• remove the same bypass from AgentPerpEngineNative
• add ERC20 and native regression tests proving stale oracle data blocks liquidation

Validation

• bun install --frozen-lockfile: pass
• git submodule update --init --recursive packages/evm-contracts/lib/solady: pass
• FOUNDRY_LIBS=["../../node_modules","lib"] forge test --match-path test/perps/AgentPerpEngine.t.sol --match-test "test(OracleStalenessBlocksLiquidation|NativeOracleStalenessBlocksLiquidation)": 2 passed
• FOUNDRY_LIBS=["../../node_modules","lib"] forge test --match-path test/perps/AgentPerpEngine.t.sol: 50 passed
• FOUNDRY_LIBS=["../../node_modules","lib"] forge test --match-path test/perps/AgentPerpEngineFuzz.t.sol: 2 passed
• FOUNDRY_LIBS=["../../node_modules","lib"] forge test --match-path test/adversarial/PmPerpsAdversarial.t.sol: 11 passed
• git diff --check: pass

Notes

Draft until owner/security review is complete. This branch targets main as the effective PR path; the same commit will be replayed into enoomian staging separately for deployment testing.