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>

.gitignore

@@ -0,0 +1,15 @@
+# Build output
+/ems
+
+# IDE
+.idea/
+.vscode/
+*.swp
+
+# Secrets — never commit real credentials
+/etc/
+viessmann-token.json
+*-token.json
+
+# Generated HTML docs
+ems-documentation.html