Butterfly EDFA Rack: Home Assistant config and dashboard

Fresh repo holding only the Butterfly-rack HA side (the firmware and BOM
live in koheron-esp32-bridge). Contents, pulled from the live HA host:

- configuration.butterfly.yaml: dBm->mW template sensors + the YAML
  dashboard registration, to merge into /config/configuration.yaml
- scripts.butterfly.yaml: the butterfly_edfa_shutdown emergency-off script
- ui-lovelace-butterfly.yaml: the dashboard
- deploy.sh: scp the dashboard, check_config, restart HA
- .gitignore guards against committing the HA DB, logs and secrets

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts.butterfly.yaml

@@ -0,0 +1,16 @@
+butterfly_edfa_shutdown:
+  alias: Butterfly EDFA emergency shutdown
+  icon: mdi:alarm-light
+  mode: single
+  sequence:
+    - service: number.set_value
+      target:
+        entity_id: number.butterfly_edfa_rack_amp_pump_current
+      data:
+        value: 0
+    - service: switch.turn_off
+      target:
+        entity_id: switch.butterfly_edfa_rack_amp_pump
+    - service: switch.turn_off
+      target:
+        entity_id: switch.butterfly_edfa_rack_seed_laser