feat: Add MET history isolation

test/services/bthome_met_history_test.dart

@@ -0,0 +1,55 @@
+import 'dart:typed_data';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:meshcore_sar_app/models/contact.dart';
+import 'package:meshcore_sar_app/services/bthome_met_history.dart';
+
+void main() {
+  test('parses a valid BTHome MET history response', () {
+    final parsed = BTHomeMetHistoryParser.parse('1,0,4,11.2,11.8,12.1,12.3');
+
+    expect(parsed.measurement, BTHomeMetMeasurement.temperature);
+    expect(parsed.page, 0);
+    expect(parsed.values, <double>[11.2, 11.8, 12.1, 12.3]);
+    expect(parsed.latest, 12.3);
+    expect(parsed.minimum, 11.2);
+    expect(parsed.maximum, 12.3);
+  });
+
+  test('rejects malformed BTHome MET history counts', () {
+    expect(
+      () => BTHomeMetHistoryParser.parse('2,0,3,41,42'),
+      throwsA(isA<BTHomeMetHistoryFormatException>()),
+    );
+  });
+
+  test('detects available BTHome MET measurements from telemetry', () {
+    final contact = Contact(
+      publicKey: Uint8List(32),
+      type: ContactType.sensor,
+      flags: 0,
+      outPathLen: 0,
+      outPath: Uint8List(64),
+      advName: 'WX',
+      lastAdvert: 0,
+      advLat: 0,
+      advLon: 0,
+      lastMod: 0,
+      telemetry: ContactTelemetry(
+        temperature: 20.1,
+        humidity: 52,
+        extraSensorData: const {'speed_2': 3.1, 'gust_2': 4.8, 'rain_2': 12.3},
+        timestamp: DateTime(2026, 3, 21, 12),
+      ),
+    );
+
+    expect(bTHomeMetMeasurementsForContact(contact), <BTHomeMetMeasurement>[
+      BTHomeMetMeasurement.temperature,
+      BTHomeMetMeasurement.humidity,
+      BTHomeMetMeasurement.windSpeed,
+      BTHomeMetMeasurement.gust,
+      BTHomeMetMeasurement.rain,
+    ]);
+    expect(supportsBTHomeMetHistory(contact), isTrue);
+  });
+}