fix(aap): Make AirPods rename actually apply on device

Switch the AAP rename packet to the opcode 0x1A format (04 00 04 00 1A 00 01 [size] 00 [name]) matching the LibrePods documentation and Linux implementation. The previous 0x1E variant (from the LibrePods Android code) was silently ignored by AirPods Pro 2 USB-C firmware — no 0x001D echo, no persistence across reconnect.

Verified on AirPods Pro 2 USB-C (firmware 81.2675...): the device now echoes the new name back via the next 0x001D INFORMATION message, and the name persists after disconnect/reconnect.

Also hardens the rename UX: gate the edit icon on isAapReady (was isAapConnected, which allowed sending during HANDSHAKING), apply an optimistic deviceInfo update with a scoped rollback on send failure, surface send errors via a new Event.SendFailed + snackbar, and restrict dialog input to ASCII with inline error feedback. Unifies send() / sendProGated() through a single sendInternal() helper so error plumbing benefits every command, not just rename.

Note: this only updates the AirPods firmware's self-reported name. Android's system Bluetooth settings read from the bond database and are not affected — renaming there still requires the Android system Bluetooth UI.

app/src/test/java/eu/darken/capod/main/ui/devicesettings/DeviceSettingsViewModelTest.kt

@@ -7,11 +7,15 @@ import eu.darken.capod.common.upgrade.UpgradeRepo
 import eu.darken.capod.monitor.core.DeviceMonitor
 import eu.darken.capod.monitor.core.PodDevice
 import eu.darken.capod.pods.core.apple.aap.AapConnectionManager
+import eu.darken.capod.pods.core.apple.aap.protocol.AapCommand
 import io.kotest.matchers.shouldBe
+import io.kotest.matchers.types.shouldBeInstanceOf
+import io.mockk.Called
 import io.mockk.coEvery
 import io.mockk.coVerify
 import io.mockk.every
 import io.mockk.mockk
+import io.mockk.verify
 import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
@@ -215,4 +219,46 @@ class DeviceSettingsViewModelTest : BaseTest() {
             coVerify(exactly = 1) { bluetoothManager.nudgeConnection(bonded) }
             vm.state.first().isForceConnecting shouldBe false
         }
+
+    @Test
+    fun `setDeviceName forwards SetDeviceName command to aapManager`() = runTest(testDispatcher) {
+        val vm = createViewModel()
+        vm.initialize(testAddress)
+        vm.state.first()
+
+        vm.setDeviceName("NewName")
+
+        coVerify { aapManager.sendCommand(testAddress, AapCommand.SetDeviceName("NewName")) }
+    }
+
+    @Test
+    fun `setDeviceName when no target address is a no-op`() = runTest(testDispatcher) {
+        val vm = createViewModel()
+        // Intentionally skip initialize — targetAddress stays null.
+
+        vm.setDeviceName("NewName")
+
+        // `any<AapCommand>()` can't be used here (AapCommand is sealed, mockk can't stub it),
+        // so verify the entire manager was not called instead.
+        verify { aapManager wasNot Called }
+    }
+
+    @Test
+    fun `setDeviceName failure emits SendFailed event`() = runTest(testDispatcher) {
+        val failure = IllegalStateException("socket closed")
+        coEvery {
+            aapManager.sendCommand(testAddress, AapCommand.SetDeviceName("NewName"))
+        } throws failure
+
+        val vm = createViewModel()
+        vm.initialize(testAddress)
+        vm.state.first()
+
+        vm.setDeviceName("NewName")
+
+        val event = vm.events.first()
+        val sendFailed = event.shouldBeInstanceOf<DeviceSettingsViewModel.Event.SendFailed>()
+        sendFailed.command shouldBe AapCommand.SetDeviceName("NewName")
+        sendFailed.message shouldBe "socket closed"
+    }
 }

app/src/test/java/eu/darken/capod/pods/core/apple/aap/devices/DefaultAapDeviceProfileNewSettingsTest.kt

@@ -128,16 +128,23 @@ class DefaultAapDeviceProfileNewSettingsTest : BaseAapSessionTest() {
         @Test fun `decode unknown returns null`() { profile.decodeSetting(settingsMessage(0x31, 0x00)).shouldBeNull() }
     }
 
-    // ── Device Rename (0x1E) ────────────────────────────────
+    // ── Device Rename (0x1A) ────────────────────────────────
+    // The working opcode is 0x1A (not the 0x1E variant in LibrePods Android); see the rationale
+    // comment in DefaultAapDeviceProfile.buildRenameMessage for the on-device test details.
 
     @Nested
     inner class DeviceRenameTests {
         @Test
-        fun `encode simple ASCII name`() {
+        fun `encode simple ASCII name full frame`() {
+            // Locks in the full wire format: header + opcode prefix (1A 00 01) + length (LE u16) + name.
             val bytes = profile.encodeCommand(AapCommand.SetDeviceName("MyPods"))
-            bytes[4] shouldBe 0x1E.toByte()
-            bytes[6] shouldBe 6.toByte() // length
-            String(bytes, 8, 6, Charsets.UTF_8) shouldBe "MyPods"
+            val expected = byteArrayOf(
+                0x04, 0x00, 0x04, 0x00,
+                0x1A, 0x00, 0x01,
+                0x06, 0x00,
+                0x4D, 0x79, 0x50, 0x6F, 0x64, 0x73,
+            )
+            bytes shouldBe expected
         }
 
         @Test
@@ -145,8 +152,9 @@ class DefaultAapDeviceProfileNewSettingsTest : BaseAapSessionTest() {
             val name = "AirPods \uD83C\uDFA7" // headphone emoji
             val nameBytes = name.toByteArray(Charsets.UTF_8)
             val bytes = profile.encodeCommand(AapCommand.SetDeviceName(name))
-            bytes[6] shouldBe nameBytes.size.toByte()
-            String(bytes, 8, nameBytes.size, Charsets.UTF_8) shouldBe name
+            bytes.size shouldBe 9 + nameBytes.size
+            bytes[7] shouldBe nameBytes.size.toByte()
+            String(bytes, 9, nameBytes.size, Charsets.UTF_8) shouldBe name
         }
 
         @Test
@@ -159,7 +167,8 @@ class DefaultAapDeviceProfileNewSettingsTest : BaseAapSessionTest() {
         fun `encode accepts 127 byte name`() {
             val name = "A".repeat(127)
             val bytes = profile.encodeCommand(AapCommand.SetDeviceName(name))
-            bytes[6] shouldBe 127.toByte()
+            bytes.size shouldBe 9 + 127
+            bytes[7] shouldBe 127.toByte()
         }
     }