Feature: DPA N-Series (#372)

* Feature: DPA N-Series support

Connects to N-Series receivers (e.g. N-DR1) via OSC over TCP.
Displays audio level, RF strength (A/B), battery status and
warnings for both channels.

* Add Lato font (bundled, offline-safe) to DPA plugin

* Add DPA plugin icon

* Fix: TCP framing, correct meter scaling

- Fix osc-tcp connection type being caught by osc SLIP handler in device.js
- Add subscriptions for tx/active, tx/name, tx/batterystatus
- Fix audio meter formula direction (was inverted)
- Scale audiolevel and rfstrength by /10 (values are dB×10)

* Fix: CSS

plugins/dpa/main.js

@@ -0,0 +1,155 @@
+const osc = require('osc');
+
+exports.config = {
+  defaultName: 'DPA N-Series',
+  connectionType: 'osc-tcp',
+  defaultPort: 1993,
+  mayChangePorts: true,
+  heartbeatInterval: 5000,
+  heartbeatTimeout: 10000,
+  searchOptions: {
+    type: 'TCPport',
+    // OSC /model message with SLIP framing: END + "/model\0\0" + ",\0\0\0" + END
+    searchBuffer: Buffer.from([
+      0xc0, 0x2f, 0x6d, 0x6f, 0x64, 0x65, 0x6c, 0x00, 0x00, 0x2c, 0x00, 0x00, 0x00, 0xc0,
+    ]),
+    testPort: 1993,
+    validateResponse(msg) {
+      const str = msg.toString();
+      return str.includes('/model') || str.includes('N-DR');
+    },
+  },
+};
+
+function makeChannel() {
+  return {
+    name: '–',
+    audioLevel: -80,
+    txActive: false,
+    txName: '',
+    battCapacity: null,
+    battTimeMin: null,
+    battHealth: null,
+    rfA: -130,
+    rfB: -130,
+    warnings: {},
+  };
+}
+
+function subscribeToAddress(device, address, intervalMs) {
+  const msgBlob = osc.writePacket({ address, args: [] });
+  device.send('/subscribe', [
+    { type: 'i', value: intervalMs },
+    { type: 'i', value: 0 },
+    { type: 'b', value: msgBlob },
+  ]);
+}
+
+exports.ready = function ready(_device) {
+  const device = _device;
+  device.data.model = '';
+  device.data.channels = [null, makeChannel(), makeChannel()];
+  device.data.warnings = {};
+
+  device.send('/settings/retrieve');
+  device.send('/model');
+
+  subscribeToAddress(device, '/ch/1/audiolevel', 100);
+  subscribeToAddress(device, '/ch/2/audiolevel', 100);
+  subscribeToAddress(device, '/advanced/1/antenna/rfstrength', 200);
+  subscribeToAddress(device, '/advanced/2/antenna/rfstrength', 200);
+  subscribeToAddress(device, '/ch/1/tx/active', 500);
+  subscribeToAddress(device, '/ch/2/tx/active', 500);
+  subscribeToAddress(device, '/ch/1/tx/name', 5000);
+  subscribeToAddress(device, '/ch/2/tx/name', 5000);
+  subscribeToAddress(device, '/ch/1/tx/batterystatus', 1000);
+  subscribeToAddress(device, '/ch/2/tx/batterystatus', 1000);
+};
+
+exports.data = function data(_device, message) {
+  const device = _device;
+  this.deviceInfoUpdate(device, 'status', 'ok');
+
+  const { address, args } = message;
+  if (!address) return;
+
+  const parts = address.split('/').filter(Boolean);
+
+  if (address === '/model') {
+    if (args && args[0]) {
+      device.data.model = args[0];
+      this.deviceInfoUpdate(device, 'defaultName', args[0]);
+    }
+  } else if (address === '/heartbeat') {
+    device.draw();
+  } else if (parts[0] === 'ch' && parts.length >= 3) {
+    const chNum = parseInt(parts[1], 10);
+    if (chNum < 1 || chNum > 2) return;
+    const ch = device.data.channels[chNum];
+    const sub = parts.slice(2).join('/');
+
+    if (sub === 'name') {
+      ch.name = (args && args[0]) ? args[0] : '–';
+      device.draw();
+    } else if (sub === 'audiolevel') {
+      ch.audioLevel = (args && args[0] !== undefined) ? args[0] / 10 : -80;
+      device.update('meterUpdate', { channels: device.data.channels });
+    } else if (sub === 'tx/active') {
+      ch.txActive = args && args[0] === 1;
+      device.draw();
+    } else if (sub === 'tx/name') {
+      ch.txName = (args && args[0]) ? args[0] : '';
+      device.draw();
+    } else if (sub === 'tx/batterystatus') {
+      if (args) {
+        ch.battCapacity = args[0] !== undefined ? args[0] : null;
+        ch.battTimeMin = args[1] !== undefined ? args[1] : null;
+        ch.battHealth = args[2] !== undefined ? args[2] : null;
+      }
+      device.draw();
+    }
+  } else if (parts[0] === 'advanced' && parts[2] === 'antenna' && parts[3] === 'rfstrength') {
+    const chNum = parseInt(parts[1], 10);
+    if (chNum < 1 || chNum > 2) return;
+    const ch = device.data.channels[chNum];
+    ch.rfA = (args && args[1] !== undefined) ? args[1] / 10 : -130;
+    ch.rfB = (args && args[2] !== undefined) ? args[2] / 10 : -130;
+    device.update('meterUpdate', { channels: device.data.channels });
+  } else if (parts[0] === 'warning') {
+    if (parts.length === 2) {
+      device.data.warnings[parts[1]] = args && args[0] === 1;
+      device.draw();
+    } else if (parts.length === 3) {
+      const chNum = parseInt(parts[1], 10);
+      if (chNum >= 1 && chNum <= 2) {
+        device.data.channels[chNum].warnings[parts[2]] = args && args[0] === 1;
+        device.draw();
+      }
+    }
+  }
+};
+
+exports.update = function update(device, doc, updateType, data) {
+  for (let i = 1; i <= 2; i++) {
+    const ch = data.channels[i];
+
+    // Audio level bar: -126 dBFS = empty, 0 dBFS = full
+    const audioOverlay = Math.max(0, Math.min(90, (1 - (ch.audioLevel + 126) / 126) * 90));
+    const $audio = doc.getElementById(`ch-${i}-audio`);
+    if ($audio) $audio.style.height = `${audioOverlay}px`;
+    const $audioText = doc.getElementById(`ch-${i}-audio-text`);
+    if ($audioText) $audioText.textContent = `${ch.audioLevel}`;
+
+    // RF bars: -130 to -50 dBm range (80 dBm span)
+    const rfANorm = Math.max(0, Math.min(1, (ch.rfA + 130) / 80));
+    const rfBNorm = Math.max(0, Math.min(1, (ch.rfB + 130) / 80));
+    const $rfA = doc.getElementById(`ch-${i}-rfa`);
+    if ($rfA) $rfA.style.height = `${(1 - rfANorm) * 90}px`;
+    const $rfB = doc.getElementById(`ch-${i}-rfb`);
+    if ($rfB) $rfB.style.height = `${(1 - rfBNorm) * 90}px`;
+  }
+};
+
+exports.heartbeat = function heartbeat(device) {
+  device.send('/settings/retrieve');
+};