Track Layerswap transactions through the explorer API

[babgev]

Summary

Replace Layerswap's solver-address/on-chain transfer tracking with ingestion from the public Layerswap explorer API.

Each swap is recorded as:

• a deposit on the source chain using the input transaction
• a withdrawal on the destination chain using the output transaction

Both legs are stored as USD-volume transactions using their individual transaction hashes and timestamps.

Why

The previous implementation inferred Layerswap activity by scanning transfers involving a maintained list of solver addresses.

The new implementation reads swap and transaction information directly from the Layerswap explorer API.

Implementation

• Add a dedicated scheduled Layerswap handler.
• Fetch completed swaps from /api/v2/explorer.
• Paginate using the starting_after cursor and stop using the close_date cutoff.
• Use the latest stored transaction as a checkpoint with a one-hour overlap.
• Process pages oldest-first and upsert rows to keep retries idempotent.
• Use each transaction's own timestamp and amount_in_usd.
• Omit legs without a valid positive USD amount.
• Map Layerswap API network identifiers to bridges-server chain keys.
• Update the advertised Layerswap network list, including EVM and non-EVM networks.
• Retry rate limits and server errors with backoff.
• Handle cancellation, invalid responses, invalid cursors, and missing configuration explicitly.
• Report unknown API networks as a degraded run without dropping recognized networks.
• Exclude Layerswap from the generic on-chain adapter scheduler.

Cutover behavior

When no API-ingestion checkpoint exists, processing starts from the deployment cutover instead of backfilling historical API data. This avoids overlapping with the period covered by the previous on-chain adapter.

Test plan

• npm run ts
• npm run build
• npm run test:server
  • 106 tests passed
  • Covers the full server, handler, helper, and utility test suite, including Layerswap API parameters, pagination, cursor handling, oldest-first processing, chain mappings, USD amounts, transaction timestamps, invalid data, and cancellation

[arkoc]

Hey @vrtnd can you please merge this PR, this is updated on top of this one: #297