Add connector infrastructure and CLI-managed Google integration

[pmbstyle]

This PR introduces the first version of a connector layer for Octopal and wires it into configuration, runtime startup, and agent visibility.

It adds connector infrastructure to the app, extends the configurator with a dedicated Connectors section, and ships the first Google connector implementation. The current supported Google service is Gmail, with an explicit CLI-managed auth flow, lifecycle commands, normalized connector state, runtime reconciliation with managed MCP servers, and read-only status visibility for Octo and workers.

Highlights:

• add connector config models and runtime manager
• add a Connectors section to octopal configure
• introduce the first Google connector implementation
• support CLI-only auth via octopal connector auth google
• add octopal connector status and octopal connector disconnect
• normalize connector state into enabled services, credentials, and auth data
• reconcile connector readiness with managed MCP startup/shutdown
• expose read-only connector status to agents/workers
• add tests covering connector config, CLI flow, lifecycle, and runtime behavior