Agentic onboarding support in parallel-cli

[sergei1152]

Summary

• migrate CLI auth to a multi-org OAuth/device-flow model with persisted control API tokens, refresh handling, and client registration
• add richer login flows (email, google, sso) plus prepaid balance commands backed by the service API
• expand skills installation flows and service/auth test coverage across the CLI

Details

• introduce structured auth storage in auth.json, including selected org state, org-scoped API keys, control API tokens, and registered client_id
• add service API helpers and generated types for app provisioning, API key creation, and prepaid balance operations
• update CLI commands to use the new auth client path for search/extract and add balance get / balance add
• add project/global skills install, uninstall, and reinstall flows, plus local standalone binary build guidance
• extend tests for auth refresh behavior, credential migration, service API requests, login UX variants, and new CLI commands