- Replace interface{} with any in providerConfigure, doRequest, get, post, put method signatures
- Replace interface{} with any in dataSourceSubscriberRead, dataSourceSystemStatsRead functions
- Replace interface{} with any in resourceSubscriberCreate/Read/Update/Delete, resourceRatingPlanCreate/Read/Update/Delete functions
- Replace map[string]interface{} with map[string]any in subscriber create/update request bodies
- Update
- Add APIClient struct with BaseURL, APIKey, and HTTPClient with 30s timeout
- Add providerConfigure to initialize client from schema with api_url and api_key
- Add doRequest helper with context support, JSON marshaling, Content-Type and Authorization headers
- Add get method accepting GET requests with 200 OK validation and JSON decoding
- Add post method accepting POST requests with 200/201 status validation and optional