feat: initial myprimal MQTT bridge service

Dynamic MySolem/MyIndygo IoT bridge with MQTT, Home Assistant
autodiscovery, and Homebridge EasyMQTT compatibility.

- Device discovery via MySolem API on startup (all modules/inputs/outputs)
- Configurable poll engine (fast/normal/slow buckets, per-input overrides)
- MQTT retained state publishing + HA autodiscovery payloads
- Unified manual command routing (linesControl vs sendManualModuleCommand)
- Runtime config via MQTT $config/set, persisted to config.json
- Expression override system (API-provided > hardcoded > passthrough)
- Minimal REST API: /health, /state, /control, /rediscover
- Docker deployment (Dockerfile + docker-compose.yml)
- 38 unit tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api-docs/pool-level-sensor.md

@@ -0,0 +1,53 @@
+# pool-level-sensor — Pool Level Float Switch (POOL-LVL-0E953B)
+
+**Module ID**: `6a174dd1e0b88ea3e925531c`  
+**Serial**: `0300020E953B0001`  
+**MAC**: `C8:B9:61:0E:95:3B`  
+**UUID**: `030058B9610E953B00000001000E953B`  
+**Firmware**: 7.3.1 | **Hardware**: B | **Manufacturer**: `03`  
+**Type**: `pool-level-sensor`  
+**Role**: Detects pool water level — triggers fill valve via LRLEVEL (lr-niv)
+
+---
+
+## Inputs
+
+| Input ID | Index | Type | Unit | Interval | Notes |
+|---|---|---|---|---|---|
+| `6a174dd1e0b88ea3e925531e` | 1 | 21 (level TOR) | raw (0/1) | 1 min | Main level switch |
+| `6a174dd1e0b88ea3e925531f` | 2 | 0 | raw | 0 (event-driven) | Secondary / aux (no telemetry recorded) |
+
+Both inputs: expression `x` (raw passthrough). `metadata.equipmentType: "waterLevel"` on input 1.
+
+### Recent readings
+
+```
+2026-05-31T14:54  1  (level OK / above threshold)
+2026-05-30T18:27  1  (level OK)
+2026-05-29T16:18  0  (level LOW — fill triggered)
+2026-05-29T16:17  1
+2026-05-29T15:59  0  (level LOW)
+```
+
+`0` = water below threshold (fill needed)  
+`1` = water level OK
+
+Only 11 events recorded over the last month — sensor only transmits on state change.
+
+---
+
+## Remote state
+
+- Battery: **41%** — low, needs replacement
+- Last radio contact: 2026-06-04T20:14:07Z
+- Relay: `60ca4276ad69dac1558f7c61` (LRMB10)
+
+The `poolLevelSensorCleaningReminder` alert (2026-05-28) confirms this device needs cleaning.
+
+---
+
+## Notes
+
+- Works in tandem with `LRLEVEL-0D2ED9` (lr-niv): when this sensor reads 0, LRLEVEL opens the fill valve
+- No programs or outputs — pure sensor
+- Type 21 = pool level TOR switch (new type, not seen in other modules)