mock-derms-dispatch-api 🎛️📡

A mock utility DERMS (Distributed Energy Resource Management System) dispatch-decision service — stands in for the real utility/aggregator side of the DER dispatch chain during development and testing. Per the ## DER Event sequence in ems/readme.md:

• Day-ahead forecast + headroom curve: not implemented — real-time monitoring only.
• Real-time: consumes dlr_rtu's live rating (MQTT) + dlr_tap_regulator_sim's live line loading (MQTT, test/line_loading/A) → trigger check. Real-time ERCOT North-zone load (NP3-562-CD) tightens the trigger margin when the zone's stressed — never an independent trigger, the local DLR trigger stays sole authority.
• On trigger: der_dispatch is a confirmed IEEE 2030.5/CSIP single-EndDevice-per-site concept, so there's no "which DER" registry — computes magnitude, POST /der-events to ems-der-control-api, the real utility-facing IEEE 2030.5 intake this mock exercises.
• Compliance return path: real IEEE 2030.5 MirrorUsagePoint intake at POST /mirror-usage-points — der-control-api reports its actual delivered power, this compares it against what was dispatched. Replaces an earlier version that subscribed directly to the broker topic ems-hmi also consumes for der_dispatch measurements, removed because a utility has no business holding broker access to a site's internal telemetry — a real utility only ever sees this over the 2030.5 HTTP surface, never raw pub/sub.
• Event-end: rating recovered (sustained, not single-sample — avoid rebound trip) → closes with CANCELLED, or max_duration_h hit → closes with COMPLETED, per IEEE 2030.5's own EventStatus.currentStatus distinction between an early cutoff and a natural expiry.

Stateless in-memory mock — no persistence. Real DERMS platforms are stateful; this one only needs to be consistent for the duration of a test run.

Instance of ~/engineering-with-ai/java-spring-jpa, with the JPA/Postgres layer removed (a mock service has no need for it) and an MQTT client added (Eclipse Paho, same as ems-der-control-api) for the broker-side consumption above.