Fixes #1728.

Problem

When a fan device exposes two fan-level properties on the same MiOT service - one with value-list (gear) and one with value-range (stepless) - the Fan entity ends up with mixed internal state:

• _prop_fan_level correctly points to the stepless prop (per the existing precedence rule),
• but _speed_names / _speed_name_map still hold the gear value-list from the earlier iteration.

The percentage property guards on if self._speed_names and self._speed_name_map, which stays truthy, so it goes down the value-list branch and calls self._speed_name_map[fan_level]. When the device reports a stepless level (e.g. 25 on xiaomi.fan.p76, 35 on xiaomi.fan.p70) the key isn't in the gear map and a KeyError is raised during async_write_ha_state -> state_attributes. The entity is stuck reporting unknown and can't be controlled.

Fix

Clear _speed_names / _speed_name_map in the value-range branch of Fan.__init__, so the percentage property falls back to ranged_value_to_percentage - which is what the in-code comment already promises ("Fan level with value-range is prior to fan level with value-list").

Reproduction

Devices affected (both verified locally):

• xiaomi.fan.p76 - urn:miot-spec-v2:device:fan:0000A005:xiaomi-p76:1:0000D062
• xiaomi.fan.p70 - urn:miot-spec-v2:device:fan:0000A005:xiaomi-p70:1:0000D062

Both expose fan-level at piid=4 (value-list [0..3]) and piid=5 (value-range [1,100,1]).

Verification

• Before fix: fan.xiaomi_de_..._p76_s_2_fan was stuck in unknown; logs showed KeyError: 25 (or 35 for p70) in fan.py:314 whenever the device pushed a state update.
• After fix + HA restart: state=on, percentage=10, preset_mode=Straight Wind, control works from HA.

Diff

                 if prop.value_range:
                     # Fan level with value-range
                     ...
                     self._attr_supported_features |= FanEntityFeature.SET_SPEED
                     self._prop_fan_level = prop
+                    # Clear any value-list state set by a previously processed
+                    # value-list fan-level prop, so that the percentage property
+                    # does not pick the value-list branch with a stale map.
+                    self._speed_names = []
+                    self._speed_name_map = {}
                 elif (
                     self._prop_fan_level is None
                     and prop.value_list
                 ):