feat: Partial support for the AC-V1-1 thermostat (#156)

## Feat. Add Support for Mysa AC-V1-1 Devices

### Overview
This PR aims to extend **mysa2mqtt** to support **Mysa AC-V1-1**
thermostats in addition to the existing baseboard models.
AC-V1 devices use different operating modes and fan modes, which
required updates to both mode translation and MQTT behavior.
Tested with `BB-V1-1` and `AC-V1-1`.

*Note: I'm no typescript expert so code might not look the best but is
fully tested*

### Key Changes
- Supports `cool`, `dry`, `fan_only`, and `auto` in addition to `off`
and `heat`.
  - New fan modes: `auto`, `low`, `medium`, `high`, and `max`.    

### Does not support yet
 - Vertical swing
 - Horizontal swing

### Technical stuff
`AC-V1-1` payload:

`"body":{"success":1,"type":2,"trig_src":3,"state":{"md":3,"sp":23.5,"lk":0,"ho":1,"br":100,"da":2,"fn":5,"ss":4,"ssh":12,"it":0}}}}`

Fan mode values: 1 = 'auto', 3 = 'low', 5 = 'medium', 7 = 'high', 8 =
'max'
**I named the value 8 max as I needed a 4th value but is not tied to
anything in HA or Mysa**

### Testing
```
npm run example

[23:13:06.300] INFO (example/3281203): [example] 'Office Room' status changed: 21.9°C, 49%, 0W
[23:13:21.701] INFO (example/3281203): [example] 'Office Room' status changed: 21.9°C, 49%, 0W
[23:13:21.938] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"heat","setPoint":23,"fanSpeed":"auto"}
[23:13:33.282] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"heat","setPoint":23.5,"fanSpeed":"auto"}
[23:13:38.132] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"heat","setPoint":23.5,"fanSpeed":"high"}
[23:13:44.380] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"fan_only","setPoint":23.5,"fanSpeed":"high"}
[23:13:52.609] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"cool","setPoint":23.5,"fanSpeed":"high"}
[23:13:57.942] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"heat","setPoint":23.5,"fanSpeed":"high"}
[23:14:01.052] INFO (example/3281203): [example] 'Family Room' state changed. {"deviceId":"<redacted>","mode":"heat","setPoint":23.5,"fanSpeed":"auto"}
```
PR to `mysa2mqtt` coming right after

src/api/MysaApiClient.ts

@@ -25,7 +25,7 @@ import { MqttPublishError, MysaApiError, UnauthenticatedError } from './Errors';
 import { Logger, VoidLogger } from './Logger';
 import { MysaApiClientEventTypes } from './MysaApiClientEventTypes';
 import { MysaApiClientOptions } from './MysaApiClientOptions';
-import { MysaDeviceMode } from './MysaDeviceMode';
+import { MysaDeviceMode, MysaFanSpeedMode } from './MysaDeviceMode';
 
 dayjs.extend(duration);
 
@@ -357,15 +357,20 @@ export class MysaApiClient {
    *
    * // Set temperature and mode
    * await client.setDeviceState('device123', 20, 'heat');
+   *
+   * // Set fan speed
+   * await client.setDeviceState('device123', undefined, undefined, 'auto');
    * ```
    *
    * @param deviceId - The ID of the device to control.
    * @param setPoint - The target temperature set point (optional).
-   * @param mode - The operating mode to set ('off', 'heat', or undefined to leave unchanged).
+   * @param mode - The operating mode to set (one of MysaDeviceMode values, or undefined to leave unchanged).
+   * @param fanSpeed - The fan speed mode to set ('low', 'medium', 'high', 'max', 'auto', or undefined to leave
+   *   unchanged).
    * @throws {@link UnauthenticatedError} When the user is not authenticated.
    * @throws {@link Error} When MQTT connection or command sending fails.
    */
-  async setDeviceState(deviceId: string, setPoint?: number, mode?: MysaDeviceMode) {
+  async setDeviceState(deviceId: string, setPoint?: number, mode?: MysaDeviceMode, fanSpeed?: MysaFanSpeedMode) {
     this._logger.debug(`Setting device state for '${deviceId}'`);
 
     if (!this._cachedDevices) {
@@ -380,6 +385,9 @@ export class MysaApiClient {
     const now = dayjs();
 
     this._logger.debug(`Sending request to set device state for '${deviceId}'...`);
+    const modeMap = { off: 1, auto: 2, heat: 3, cool: 4, fan_only: 5, dry: 6 };
+    const fanSpeedMap = { auto: 1, low: 3, medium: 5, high: 7, max: 8 };
+
     const payload = serializeMqttPayload<ChangeDeviceState>({
       msg: InMessageType.CHANGE_DEVICE_STATE,
       id: now.valueOf(),
@@ -398,6 +406,8 @@ export class MysaApiClient {
         ver: 1,
         type: device.Model.startsWith('BB-V1')
           ? 1
+          : device.Model.startsWith('AC-V1')
+            ? 2
             : device.Model.startsWith('BB-V2')
               ? device.Model.endsWith('-L')
                 ? 5
@@ -407,7 +417,8 @@ export class MysaApiClient {
           {
             tm: -1,
             sp: setPoint,
-            md: mode === 'off' ? 1 : mode === 'heat' ? 3 : undefined
+            md: mode ? modeMap[mode] : undefined,
+            fn: fanSpeed ? fanSpeedMap[fanSpeed] : undefined
           }
         ]
       }
@@ -792,15 +803,33 @@ export class MysaApiClient {
             });
             break;
 
-          case OutMessageType.DEVICE_STATE_CHANGE:
+          case OutMessageType.DEVICE_STATE_CHANGE: {
+            const modeMap: Record<number, MysaDeviceMode> = {
+              1: 'off',
+              2: 'auto',
+              3: 'heat',
+              4: 'cool',
+              5: 'fan_only',
+              6: 'dry'
+            };
+            const fanSpeedMap: Record<number, MysaFanSpeedMode> = {
+              1: 'auto',
+              3: 'low',
+              5: 'medium',
+              7: 'high',
+              8: 'max'
+            };
+
             this.emitter.emit('stateChanged', {
               deviceId: parsedPayload.src.ref,
-              mode: parsedPayload.body.state.md === 1 ? 'off' : parsedPayload.body.state.md === 3 ? 'heat' : undefined,
-              setPoint: parsedPayload.body.state.sp
+              mode: parsedPayload.body.state.md ? modeMap[parsedPayload.body.state.md] : undefined,
+              setPoint: parsedPayload.body.state.sp,
+              fanSpeed: parsedPayload.body.state.fn !== undefined ? fanSpeedMap[parsedPayload.body.state.fn] : undefined
             });
             break;
           }
         }
+      }
     } catch (error) {
       this._logger.error('Error handling MQTT message:', error);
     }

src/api/MysaDeviceMode.ts

@@ -4,4 +4,11 @@
  * Defines the possible operational states that a Mysa thermostat or heating device can be set to. These modes control
  * the device's heating behavior and power consumption.
  */
-export type MysaDeviceMode = 'off' | 'heat';
+export type MysaDeviceMode = 'off' | 'heat' | 'cool' | 'dry' | 'fan_only' | 'auto';
+
+/**
+ * Union type representing the available fan speed modes for Mysa devices.
+ *
+ * Defines the possible fan speed states that a Mysa thermostat device can be set to.
+ */
+export type MysaFanSpeedMode = 'auto' | 'low' | 'medium' | 'high' | 'max';

src/api/events/StateChange.ts

@@ -1,4 +1,4 @@
-import { MysaDeviceMode } from '@/api/MysaDeviceMode';
+import { MysaDeviceMode, MysaFanSpeedMode } from '@/api/MysaDeviceMode';
 
 /**
  * Interface representing a device state change event for a Mysa device.
@@ -14,4 +14,6 @@ export interface StateChange {
   mode?: MysaDeviceMode;
   /** Current temperature setpoint after the state change */
   setPoint: number;
+  /** Optional fan speed (1 = auto, 3 = low, 5 = medium, 7 = high, 8 = max). AC only */
+  fanSpeed?: MysaFanSpeedMode;
 }

src/types/mqtt/in/ChangeDeviceState.ts

@@ -36,6 +36,8 @@ export interface ChangeDeviceState extends MsgPayload<InMessageType.CHANGE_DEVIC
         md?: number;
         /** Unknown, should always be -1 */
         tm: number;
+        /** Optional fan speed (1 = auto, 3 = low, 5 = medium, 7 = high, 8 = max). AC only */
+        fn?: number;
       }
     ];
     /**

src/types/mqtt/out/DeviceStateChange.ts

@@ -25,10 +25,12 @@ export interface DeviceStateChange extends MsgPayload<OutMessageType.DEVICE_STAT
       ho: number;
       /** Unknown */
       lk: number;
-      /** Device mode (1 = OFF, 3 = HEAT) */
+      /** Device mode (1 = OFF, 2 = AUTO, 3 = HEAT, 4 = COOL, 5 = FAN_ONLY, 6 = DRY) */
       md: number;
       /** Temperature setpoint */
       sp: number;
+      /** Optional fan speed (1 = auto, 3 = low, 5 = medium, 7 = high, 8 = max). AC only */
+      fn?: number;
     };
     /** Success indicator for the state change operation (1 = success, 0 = failure) */
     success: number;

src/types/rest/States.ts

@@ -50,6 +50,8 @@ export interface DeviceState {
   Humidity: TimestampedValue<number>;
   /** Lock status */
   Lock: TimestampedValue<number>;
+  /** Fan speed */
+  FanSpeed?: TimestampedValue<number>;
 }
 
 /**