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>

src/mqtt/commands.js

@@ -0,0 +1,56 @@
+'use strict';
+const { getClient, getPrefix, publish } = require('./client');
+const { allOutputs } = require('../registry');
+const { sendCommand } = require('../control');
+
+function subscribeAll() {
+  const client = getClient();
+  if (!client) return;
+  const prefix = getPrefix();
+
+  for (const out of allOutputs()) {
+    const topic = `${prefix}/${out.moduleSlug}/output/${out.index}/set`;
+    client.subscribe(topic);
+  }
+
+  client.on('message', async (topic, buf) => {
+    const prefix_ = `${prefix}/`;
+    if (!topic.startsWith(prefix_)) return;
+
+    // Match: {prefix}/{slug}/output/{index}/set
+    const parts = topic.slice(prefix_.length).split('/');
+    if (parts.length !== 4 || parts[1] !== 'output' || parts[3] !== 'set') return;
+
+    const [slug, , indexStr] = parts;
+    const outputIndex = parseInt(indexStr, 10);
+
+    let cmd;
+    try {
+      cmd = JSON.parse(buf.toString());
+    } catch {
+      console.warn(`[commands] Invalid JSON on ${topic}`);
+      return;
+    }
+
+    // Find module by slug
+    const output = allOutputs().find(o => o.moduleSlug === slug && o.index === outputIndex);
+    if (!output) {
+      console.warn(`[commands] No output found for ${slug}/output/${outputIndex}`);
+      return;
+    }
+
+    try {
+      await sendCommand(output.moduleId, outputIndex, cmd);
+      // Reflect running state optimistically
+      const stateValue = (cmd.action === 'run' || cmd.action === 'boost') ? 1 : 0;
+      publish(`${slug}/output/${outputIndex}/state`, { value: stateValue, ts: new Date().toISOString() });
+      console.log(`[commands] ${slug}/output/${outputIndex} → ${cmd.action}`);
+    } catch (e) {
+      console.error(`[commands] Command failed for ${slug}/output/${outputIndex}:`, e.message);
+    }
+  });
+
+  console.log(`[commands] Subscribed to ${allOutputs().length} output set topics`);
+}
+
+module.exports = { subscribeAll };