Read access to Alerts via the public API

Today POST /v1/alerts (push only) is the only alert endpoint - there's no GET/list, so we can't poll alert state, tune noise programmatically, or build alert-aware automation. Tickets, Assets, Clients and Contacts are all fully exposed via the API; Alerts is the one major gap. Read access here would let partners build their own triage/reporting layers instead of relying only on the in-app Alerts view.