Fetches the list of Google contacts using the provided access token.
OAuth access token.
An array of Google contact objects.
Fetches contact groups and returns a mapping of lowercase group name → group ID.
OAuth access token.
Record mapping lowercase group names to their resource IDs.
Core service responsible for interacting with Google contacts and Contact Groups APIs.
Encapsulates logic for fetching, processing, and transforming Google contact data. Designed to be used by higher-level plugin components to separate external API concerns from application and Obsidian-specific logic.