fix(inventory): Fix cross-chain refund under-counting in BundleDataApproxClient

[nicholaspai]

Summary

• Bug: BundleDataApproxClient.getApproximateRefundsForToken filtered fills using fromBlocks[fillChain], which is derived from the last executed bundle on the fill chain. When a bundle was executed on the fill chain but the root bundle relay had not yet propagated to the repayment chain (normal cross-chain delay of ~10-20 minutes), fills with cross-chain repayment were incorrectly excluded from upcoming refunds. This caused the relayer to under-estimate pending refunds on the repayment chain during the relay propagation window.
• Fix: getUnexecutedBundleStartBlocks now returns a 2D block mapping (result[referenceChain][fillChain]) containing the matched bundle's end blocks for all chains, not just the reference chain. Refund filtering uses fromBlocks[repaymentChainId][fillChain] so fills are only excluded when the repayment chain's refund leaf has actually been executed. Deposit filtering uses the diagonal (fromBlocks[chainId][chainId]), preserving existing behavior.
• Test: Added regression test that creates a fill on chain A with repayment on chain B, where chain A has executed the bundle but chain B has not received the relay. Verifies the fill is correctly counted as an upcoming refund on chain B.

Root cause

Each bundle cycle, the dataworker executes a bundle on the hub chain and then relays root bundles to each spoke chain. On the hub chain (Ethereum), execution is immediate since it's same-chain. On L2s, the relay takes 10-20+ minutes to propagate. The BundleDataApproxClient typically runs shortly after a new bundle is proposed — at which point the previous bundle's relay may not have reached all spoke chains yet.

The old code computed a 1D fromBlocks[chainId] per chain based on that chain's own spoke pool events. A fill on chain X with repaymentChainId = Y was filtered by fromBlocks[X]. When chain X advanced (bundle executed there) but chain Y hadn't received the relay, the fill was excluded even though the relayer hadn't received the refund on chain Y.

Changes

File	Change
src/clients/BundleDataApproxClient.ts	getUnexecutedBundleStartBlocks returns 2D mapping; getApproximateRefundsForToken indexes by [repaymentChainId][fillChainId]; getApproximateDepositsForToken uses diagonal
test/BundleDataApproxClient.ts	New regression test for cross-chain relay delay scenario; updated existing tests for 2D structure
test/mocks/MockSpokePoolClient.ts	Added addRelayerRefundExecution method (replaces as any cast)
test/mocks/MockBundleDataApproxClient.ts	Updated override signatures to match 2D types

Test plan

• All existing BundleDataApproxClient tests pass (10/10)
• New regression test verifies cross-chain refund counting with relay delay
• Verify no impact on inventory rebalancing behavior in staging

🤖 Generated with Claude Code

[pxrl]

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