Initial commit: EMS — Energie Management System

Complete self-consumption optimisation system for 7 kWp PV installation:
- Prometheus collector (grid power, SOC, PV, per-phase, compressor)
- Pure decision engine with SOC gates, hysteresis, priority ordering
- Shelly Gen1/Gen2 actuator (SHA-256 Digest auth, PM power readback)
- Viessmann OAuth2 client for DHW temperature control
- PV forecast integration (forecast.solar)
- Wallbox mutual exclusion (VX3 4.6 kW AC output constraint)
- Car-not-charging detection via Shelly PM
- Compressor idle → early SG-Ready release
- Per-phase grid power for single-phase wallbox decisions
- Manual override detection and web UI with override buttons
- Full unit test coverage for decision engine
- systemd service, Makefile, complete documentation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Makefile

@@ -0,0 +1,26 @@
+BINARY := ems
+CONFIG := configs/ems-config.yaml
+
+.PHONY: build test dry-run run install lint
+
+build:
+	go build -o $(BINARY) .
+
+test:
+	go test ./...
+
+dry-run: build
+	./$(BINARY) -config $(CONFIG) -dry-run
+
+run: build
+	./$(BINARY) -config $(CONFIG)
+
+install: build
+	install -Dm755 $(BINARY) /usr/local/bin/$(BINARY)
+	install -Dm644 $(CONFIG) /etc/ems/ems-config.yaml
+	install -Dm644 systemd/ems.service /etc/systemd/system/ems.service
+	systemctl daemon-reload
+	@echo "Run: systemctl enable --now ems"
+
+lint:
+	go vet ./...