staticaddr/withdraw: add retry and reorg handling for withdrawals

[kaldun-tech]

Summary

Fixes Issue #1087

Addresses three related issues in the static address withdrawal manager:

1. No retry on registration failure - RegisterSpendNtfn / RegisterConfirmationsNtfn failures silently stopped monitoring
2. No reorg handling - Reorged transactions weren't re-registered
3. State persistence race - handleWithdrawal failure prevented state persistence, breaking recovery

Changes

• Reorder state persistence to happen BEFORE handleWithdrawal so recovery works even if monitoring setup fails
• Add retry-on-next-block for registration failures
• Add reorg detection via lndclient.WithReOrgChan() - on reorg after spend detection, returns to spend watching (not just confirmation re-registration) since the spend tx itself may be invalidated
• Make handleWithdrawal async/best-effort since tx is already published

Design Note: Best-Effort Monitoring

After WithdrawDeposits publishes the transaction and persists deposits to Withdrawing state, subsequent operations (withdrawal record creation, spend monitoring) are best-effort. Errors are logged but don't fail the RPC API call because:

1. The user's funds are safe after the tx is broadcast
2. State is persisted because deposits are in Withdrawing state
3. recoverWithdrawals will retry monitoring on restart

Testing

Unit tests added for retry logic and clean shutdown:

• TestHandleWithdrawal_HappyPath
• TestHandleWithdrawal_SpendRegistrationRetry
• TestHandleWithdrawal_ConfirmationRegistrationRetry
• TestHandleWithdrawal_ContextCanceled
• TestHandleWithdrawal_BlockChannelClosed
• TestHandleWithdrawal_SpendErrorReregisters

I decided to defer tests related to reorg. These would require MockChainNotifier extension to capture lndclient.NotifierOption

# Withdraw tests
go test ./staticaddr/withdraw/...

# Linting via make requires docker
make lint
# No docker
golangci-lint run ./staticaddr/withdraw/...

Questions for Maintainers

1. RBF hash cleanup: When an RBF (Replace-By-Fee) replacement confirms, SpenderTxHash is used to delete from finalizedWithdrawalTxns. If the original tx was fee-bumped, does the original txHash remain in the map? Should both be cleaned up?
2. Variable naming: The allDeposited flag indicates first withdrawal vs fee bump. How about we rename this to isFirstWithdrawal for clarity?

Pull Request Checklist

• Update release_notes.md if your PR contains major features, breaking changes or bugfixes

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request improves the reliability of the static address withdrawal manager by addressing critical gaps in error handling and state management. By introducing robust retry mechanisms for notification registration, implementing reorg detection, and ensuring state is persisted before monitoring begins, the system is now more resilient to transient chain issues and process restarts.

Highlights

• Robust Withdrawal Monitoring: Implemented automatic retry logic for registration failures, ensuring that monitoring does not silently stop if notification registration fails.
• Reorg Handling: Integrated reorg detection using lndclient's WithReOrgChan, allowing the manager to correctly re-register for spend notifications if a transaction is invalidated by a reorg.
• State Persistence Ordering: Reordered state persistence to occur before monitoring setup, ensuring that recovery processes can correctly identify and resume pending withdrawals after a restart.

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[gemini-code-assist]

Code Review

This pull request enhances the reliability of static address withdrawals by implementing automatic retries for notification registrations and robust handling for blockchain reorgs. It also reorders state persistence to ensure that withdrawals can be recovered correctly after a restart. The review feedback identifies several opportunities to harden the implementation, specifically by handling potential channel closures to prevent panics or tight loops during shutdown, and ensuring that the correct transaction hash is cleared from the internal tracking map when Replace-By-Fee (RBF) transactions are confirmed.

[kaldun-tech]

@hieblmi Ready for review

[lightninglabs-deploy]

@kaldun-tech, remember to re-request review from reviewers when ready

[kaldun-tech]

@hieblmi @ffranr @alexbosworth @starius Sorry for ping, reminder to review

[kaldun-tech]

Doing additional review and adding tests. Please stand by.

[kaldun-tech]

I'd like to rename the allDeposited variable to isFirstWithdrawal to better reflect how it's being used here

[kaldun-tech]

Ready for review. Added inline comments on two areas where I'd appreciate maintainer input.

[kaldun-tech]

I added a defensive nil check here.

My concern in the RBF (Replace-By-Fee) is the case where when the replacement confirms, the replacement's hash is used to delete here. But the original txHash was added to the map initially. Does it remain as a leak? Should both be cleaned up here or does the map get cleared via another path?