R Client for the ZENTRA Cloud V5 API // Downloads environmental sensor data from the ZENTRA Cloud V5 API (https://api.zentracloud.io) into tidy data frames. Provides device discovery, reading retrieval with automatic pagination and rate-limit handling, tidy long output with a wide-format helper, and an incremental 'sync' engine with pluggable local storage (RDS files, CSV files, or return-only) so that new readings can be fetched on a schedule and appended to a growing local record.