fix(config_flow): 🐛 stop DHCP discovery double-reloading config entries

[rhammen]

🐞 Problem

WARNING (MainThread) [homeassistant.helpers.frame] Detected that custom integration 'luxtronik2' has an update listener and should use it for scheduling a reload. This will stop working in Home Assistant 2026.12.0, please create a bug report at https://github.com/BenPru/luxtronik/issues

🔍 Root cause

__init__.py registers a generic update listener (entry.add_update_listener(update_listener)) whose body unconditionally calls hass.config_entries.async_reload(...). Home Assistant fires update_listeners on any entry change, not just options-flow changes — including data changes.

async_step_dhcp in config_flow.py calls _abort_if_unique_id_configured(updates={...}) to silently keep a rediscovered device's host/port in sync. That data update:

• immediately fires our own update_listener, which schedules a reload, and
• separately, since reload_on_update defaults to True, core also schedules its own reload for the same entry, logging this deprecation warning in the process.

So a single DHCP rediscovery currently triggers two redundant reload schedules for the same entry. HA is deprecating this combination and it will stop working in 2026.12.0.

🔧 Fix

Pass reload_on_update=False to _abort_if_unique_id_configured in async_step_dhcp, since our own update listener already reloads the entry whenever its data changes. Core no longer needs to (and shouldn't) schedule a second reload.

🧪 Testing

• pytest -k dhcp -q — 5 passed
• ruff check — clean
• basedpyright — 0 errors

✅ Test plan

• Confirm DHCP rediscovery of an already-configured heat pump at a new IP still updates the entry's host/port
• Confirm the deprecation warning no longer appears in the log after a DHCP rediscovery event

🤖 Generated with Claude Code