MON-4025: Add CaaS transaction split methods

[ingridacero]

Description

Implements MON-4025: CaaS transaction split support in @mft/moneyhub-api-client, aligned with api-gateway (MON-4023).

Added

• caasPutTransactionSplits: PUT /accounts/{accountId}/transactions/{transactionId}/splits, scope caas:transaction_splits:write, body { data: splits }, returns ApiResponse with split data (amount, userCategoryId, description)
• caasDeleteTransactionSplits: DELETE on the same path, scope caas:transaction_splits:delete, returns HTTP 204

Screenshots, Recordings

This PR includes:

• Unit tests
• Contract tests
• Logging
• Monitoring
• Dependencies updates
• Swagger/Documentation changes

Added config changes?

• Yes, add more details and remember to add them in ETCD
• No

Added database migrations/resources (db, collection, table, column)?

• Yes, please add more details and get them 'signed off' by devsecops team (add them to the PR)
• No

Are there any post deployment tasks that need to be performed?

Publish a new @mft/moneyhub-api-client version after merge. Consumers need tokens with caas:transaction_splits:write and caas:transaction_splits:delete for the new methods. Run npm run test-caas against an environment with api-gateway splits deployed.

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Note

Low Risk
Additive client API and docs/tests only; no changes to auth, existing CAAS transaction flows, or shared request core beyond registering the new module.

Overview
Adds CaaS transaction split support to the API client: caasPutTransactionSplits (PUT, scope caas:transaction_splits:write, body { data: splits }, returns upserted splits) and caasDeleteTransactionSplits (DELETE, scope caas:transaction_splits:delete, returns HTTP 204).

New request module src/requests/caas/transaction-splits.ts and types are wired into the client export list. README documents both methods; CLI examples under examples/caas/ exercise put (inline JSON or file) and delete. Integration tests cover PUT (Swagger validation + response shape) and DELETE (enrich → put → delete → 204).

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