Fixed:
- A lone transient error from the BLUETTI cloud no longer fails the whole poll. A single HTTP 502/503/504 from the gateway, or a network timeout, is retried once immediately - the Modbus coordinator's own reasoning - and only a second failure marks the device's entities unavailable until the next poll. Before, one 504 after ~10 s (about one poll in thirty on 2026-09-18, gone on the next) logged an ERROR and made every entity unavailable for 30 s. (#53, #54)
- The error message names the cause:
BLUETTI cloud answered HTTP 504 Gateway Timeout (code 504)instead of[504] An unknown error has occurred., so a user can tell BLUETTI's side from their own setup. Requires pybluetti 0.2.5. (#54)
Internal:
- The deprecated Modbus coordinator's device union knows AC200L (bluetti-modbus 0.22.0), keeping type checks green. (#54)