fix(debug): send typed characters to the mirrored device

The mirror's keyboard capture only mapped navigation keys and silently
dropped everything else, so text entry did nothing: printable characters
never left the client even though the firmware already injects kb_char.
Characters now go out as ANYKEY with the code point, Backspace goes as a
character (so text fields delete rather than navigating back, which stays
Esc's job), and the handling moves into a Modifier.remoteKeyInput
extension.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/debugging/DisplayMirror.kt

@@ -55,10 +55,12 @@ import androidx.compose.ui.focus.onFocusChanged
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.hapticfeedback.HapticFeedbackType
+import androidx.compose.ui.input.key.Key
 import androidx.compose.ui.input.key.KeyEventType
 import androidx.compose.ui.input.key.key
 import androidx.compose.ui.input.key.onPreviewKeyEvent
 import androidx.compose.ui.input.key.type
+import androidx.compose.ui.input.key.utf16CodePoint
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.platform.LocalHapticFeedback
@@ -160,6 +162,7 @@ fun DisplayMirrorContent(modifier: Modifier = Modifier, viewModel: DisplayMirror
                     hasTouch = displayInfo?.has_touch == true,
                     onEvent = viewModel::sendKey,
                     onTouch = viewModel::sendTouch,
+                    onChar = viewModel::sendChar,
                 )
         }
     }
@@ -175,6 +178,7 @@ private fun MirrorWithControls(
     hasTouch: Boolean,
     onEvent: (Int) -> Unit,
     onTouch: (Int, Int, Int) -> Unit,
+    onChar: (Int) -> Unit,
 ) {
     BoxWithConstraints(modifier = Modifier.fillMaxWidth()) {
         if (maxWidth >= SIDE_BY_SIDE_MIN_WIDTH) {
@@ -183,7 +187,15 @@ private fun MirrorWithControls(
                 verticalAlignment = Alignment.CenterVertically,
                 modifier = Modifier.fillMaxWidth(),
             ) {
-                MirrorSurface(frame, palette, hasTouch, onEvent, onTouch, modifier = Modifier.weight(1f, fill = false))
+                MirrorSurface(
+                    frame,
+                    palette,
+                    hasTouch,
+                    onEvent,
+                    onTouch,
+                    onChar,
+                    modifier = Modifier.weight(1f, fill = false),
+                )
                 DpadCluster(enabled = enabled, onEvent = onEvent)
             }
         } else {
@@ -192,7 +204,7 @@ private fun MirrorWithControls(
                 verticalArrangement = Arrangement.spacedBy(12.dp),
                 modifier = Modifier.fillMaxWidth(),
             ) {
-                MirrorSurface(frame, palette, hasTouch, onEvent, onTouch)
+                MirrorSurface(frame, palette, hasTouch, onEvent, onTouch, onChar)
                 DpadCluster(enabled = enabled, onEvent = onEvent)
             }
         }
@@ -212,6 +224,7 @@ private fun MirrorSurface(
     hasTouch: Boolean,
     onEvent: (Int) -> Unit,
     onTouch: (Int, Int, Int) -> Unit,
+    onChar: (Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val focusRequester = remember { FocusRequester() }
@@ -232,12 +245,7 @@ private fun MirrorSurface(
             Modifier.focusRequester(focusRequester)
                 .onFocusChanged { focused = it.isFocused }
                 .focusable()
-                .onPreviewKeyEvent { event ->
-                    val mapped = keyToInputEvent(event.key) ?: return@onPreviewKeyEvent false
-                    // Consume KeyUp of mapped keys too, or Space/arrows leak to the scroll container.
-                    if (event.type == KeyEventType.KeyDown) onEvent(mapped)
-                    true
-                }
+                .remoteKeyInput(onEvent, onChar)
                 .pointerInput(hasTouch) {
                     detectTapGestures(
                         onTap = { offset ->
@@ -295,6 +303,35 @@ private fun MirrorControlHints(focused: Boolean, hasTouch: Boolean, onToggleKeyb
     }
 }
 
+/**
+ * Sends captured key presses to the device: mapped navigation keys as input events, Backspace and printable characters
+ * as typed characters. Handled keys are consumed on both down and up so nothing leaks into the surrounding scroll
+ * container.
+ */
+private fun Modifier.remoteKeyInput(onEvent: (Int) -> Unit, onChar: (Int) -> Unit): Modifier =
+    onPreviewKeyEvent { event ->
+        val down = event.type == KeyEventType.KeyDown
+        val mapped = keyToInputEvent(event.key)
+        when {
+            mapped != null -> {
+                if (down) onEvent(mapped)
+                true
+            }
+
+            event.key == Key.Backspace -> {
+                if (down) onChar(CHAR_BACKSPACE)
+                true
+            }
+
+            event.utf16CodePoint >= FIRST_PRINTABLE_CHAR -> {
+                if (down) onChar(event.utf16CodePoint)
+                true
+            }
+
+            else -> false
+        }
+    }
+
 /** Converts a completed drag into one direction event along its dominant axis, ignoring short accidental swipes. */
 private fun Modifier.swipeToDirection(onEvent: (Int) -> Unit): Modifier = pointerInput(Unit) {
     val threshold = SWIPE_THRESHOLD.toPx()

feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/debugging/DisplayMirrorUtils.kt

@@ -34,6 +34,16 @@ internal const val INPUT_RIGHT = 20
 internal const val INPUT_BACK = 27
 internal const val INPUT_USER_PRESS = 28
 
+// ANYKEY carries a character in kb_char rather than a navigation code.
+internal const val INPUT_ANYKEY = 0xFF
+
+// LVGL's backspace key value; typed as a character so text fields delete
+// rather than navigating back (which is what Esc is for).
+internal const val CHAR_BACKSPACE = 8
+
+// Below this, key events are control codes rather than typable text.
+internal const val FIRST_PRINTABLE_CHAR = 32
+
 /** Scales a tap position on the scaled-up mirror image back to panel pixel coordinates. */
 internal fun Offset.toDeviceX(boxWidthPx: Int, frame: MirrorFrame): Int =
     (x / boxWidthPx * frame.width).toInt().coerceIn(0, frame.width - 1)
@@ -55,9 +65,7 @@ internal fun keyToInputEvent(key: Key): Int? = when (key) {
     Key.Spacebar,
     -> INPUT_SELECT
 
-    Key.Escape,
-    Key.Backspace,
-    -> INPUT_BACK
+    Key.Escape -> INPUT_BACK
 
     else -> null
 }

feature/settings/src/commonMain/kotlin/org/meshtastic/feature/settings/debugging/DisplayMirrorViewModel.kt

@@ -83,6 +83,9 @@ class DisplayMirrorViewModel(
 
     fun sendKey(eventCode: Int) = adminController.sendInputEvent(eventCode)
 
+    /** Forwards a typed character; the device UI receives it as a key press rather than a navigation event. */
+    fun sendChar(codePoint: Int) = adminController.sendInputEvent(INPUT_ANYKEY, kbChar = codePoint)
+
     /** Forwards a tap/long-press on the mirrored image as a device touch event with panel coordinates. */
     fun sendTouch(eventCode: Int, x: Int, y: Int) = adminController.sendInputEvent(eventCode, touchX = x, touchY = y)