[adt-auth] Implement BTP Service Key auth plugin in @abapify/adt-auth #71
Description
Implement a new authentication plugin for BTP Service Key inside the @abapify/adt-auth package by migrating the legacy ServiceKeyParser, BTPServiceKey, and UAACredentials types from packages/adt-cli/src/lib/auth-utils.ts.
- Create new plugin in src/plugins/service-key.ts
- Must implement AuthPlugin interface (authenticate(options)):
- Accept serviceKeyJson: string | object
- Use ServiceKeyParser to validate and extract credentials
- Fetch OAuth2 client_credentials token if required (serviceKey.uaa.url/oauth/token)
- Return either CookieAuthResult or BasicAuthResult depending on extracted credential type
- Ensure plugin is exported in tsdown.config.ts and src/index.ts
- Migrate PKCE/OAuth helpers from oauth-utils.ts to src/utils/pkce.ts
- Remove old files from adt-cli (auth-utils.ts, oauth-utils.ts) once migration complete
Parent Epic: #70