v4 - Client rewritten to align against Tradera REST API instead of SOAP

The client has been rewritten against Tradera's REST API v4. It replaces the SOAP
client this repo shipped through 1.5.1.

New package name

This ships as tradera-api on npm:

npm install tradera-api

The SOAP client keeps its own name, tradera-soap-api-client, and its source lives on
the archive/v3 branch. Existing 1.x installs keep working. They just won't get new
features, since Tradera now points new integrations at the REST API.

If you saw a 0.1.0 on npm, that was a placeholder publish to hold the name. 4.0.0 is
the first real release under it.

New versioning

The new package will now be more closely versioned against Tradera version number.

The major version of this package tracks the major version of the Tradera REST API it targets. This client is 4.x, so it speaks Tradera REST API v4. If Tradera ships a v5, this package moves to 5.x.

That has one consequence worth knowing about before you pin a range:

• Major changes only when the targeted Tradera API major changes.
• Minor covers everything else that is user visible, including breaking changes to this package's own API. A minor bump is not guaranteed to be backwards compatible.
• Patch is for fixes that do not change the public API.

What's in it

Everything is generated from Tradera's OpenAPI definition rather than WSDL, so methods
and responses are typed from the contract instead of hand-maintained. The soap and
ts-node runtime dependencies are gone. openapi-fetch is the only one left.

Clients are constructed now, not awaited:

// 1.x, SOAP
const client = await createSearchClient({ appId, appKey });

// 4.x
const client = new TraderaSearchClient({ appId, appKey });