- Create ApiClient class wrapping fetch() with configurable baseUrl - Implement typed methods for all 21+ REST endpoints: - Projects: list, create, get, delete - Goals: list, create - Nodes: get, update, createChild - Edges: create, delete - Goal trees and task views: tree, list tasks, ready tasks, next task - Decisions: list, history, export - Graph: export all goals, export single goal, import, diff - Sessions: list, get - Search: nodes - Agents: list - Health: check status - Define ApiError class with status code and message - Proper error handling: throw on 4xx/5xx, return undefined for 204 - Support optional request bodies with Content-Type header