Adding second cloud account overwrites first config entry's data

[Werwoifna]

Reproduction:

Add integration with Cloud Account A → loads Heat Pump A correctly
Add second integration with Cloud Account B → both integrations now show Heat Pump A's data
Restart HA, delete A, add A again → A works alone
Add B → both show A again

Expected: Each config entry isolates its own credentials and target heat pump
Actual: Adding a second config entry overwrites/shares state with the first
Likely cause: shared cache, singleton API client, or global session state not partitioned per config entry.