fix car sensor channel, mark Metrolist working

Sensors live in service field 2, not 5 (that's the mic), so the channel never opened.
Message ids were also one off and the start request was missing min_update_period.

gearslip/src/test/java/app/seb3thehacker/gearslip/ServiceDiscoverySensorTest.kt

@@ -0,0 +1,38 @@
+package app.seb3thehacker.gearslip
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+
+/**
+ * The 2018 Uconnect's sensor and mic services, from `archive/spike/car-run-2026-09-16-run2.log`.
+ * Channel 7 offers sensors in Service field 2; channel 3 is the mic in field 5. Reading the wrong
+ * field finds nothing at all, so the sensor channel never opens.
+ */
+class ServiceDiscoverySensorTest {
+
+    private fun varintField(field: Int, value: Long) = Protobuf.varintField(field, value)
+
+    private fun lenField(field: Int, body: ByteArray): ByteArray =
+        Protobuf.varint(((field shl 3) or 2).toLong()) + Protobuf.varint(body.size.toLong()) + body
+
+    private fun micSource() = lenField(
+        1,
+        varintField(1, 3L) + lenField(5, varintField(1, 1L) + lenField(2, varintField(1, 16_000L))),
+    )
+
+    private fun sensorSource(types: List<Int>): ByteArray {
+        val sensors = types.fold(ByteArray(0)) { acc, t -> acc + lenField(1, varintField(1, t.toLong())) }
+        return lenField(1, varintField(1, 7L) + lenField(2, sensors + varintField(2, 256L)))
+    }
+
+    @Test
+    fun findsUconnectSensorsInFieldTwo() {
+        val response = micSource() + sensorSource(listOf(1, 3, 10, 13, 20, 21))
+        val sensors = ServiceDiscovery.findSensorService(response)
+        assertNotNull(sensors)
+        sensors!!
+        assertEquals(7, sensors.serviceId)
+        assertEquals(listOf(1, 3, 10, 13, 20, 21), sensors.types)
+    }
+}