fix(mobile): send terminal delete from software keyboard

apps/mobile/modules/t3-terminal/ios/T3TerminalView.swift

@@ -137,6 +137,7 @@ private enum TerminalInputSequence {
 private final class TerminalInputField: UITextField {
   var onDeleteBackward: (() -> Void)?
   var onInsert: ((String) -> Void)?
+  private let deletionRouter = TerminalDeletionRouter()
 
   private static let hardwareKeyCommands = TerminalHardwareKeyEncoder.makeKeyCommands(
     action: #selector(handleHardwareKeyCommand(_:))
@@ -147,8 +148,14 @@ private final class TerminalInputField: UITextField {
   }
 
   override func deleteBackward() {
-    onDeleteBackward?()
-    super.deleteBackward()
+    deletionRouter.deleteBackward(
+      emit: { [weak self] in self?.onDeleteBackward?() },
+      performSystemDelete: { super.deleteBackward() }
+    )
+  }
+
+  func reportEmptyReplacement() {
+    deletionRouter.emptyReplacement { [weak self] in self?.onDeleteBackward?() }
   }
 
   @objc
@@ -410,6 +417,11 @@ public final class T3TerminalView: ExpoView, UITextFieldDelegate {
       return false
     }
 
+    // Some software keyboards report deletion here without calling deleteBackward.
+    // The field suppresses a duplicate if UIKit also calls this delegate from super.deleteBackward.
+    if textField === inputField {
+      inputField.reportEmptyReplacement()
+    }
     return false
   }
 

apps/mobile/modules/t3-terminal/ios/TerminalDeletionRouter.swift

@@ -0,0 +1,17 @@
+/// Sends one terminal DEL for either UITextField deletion callback path.
+/// `super.deleteBackward()` may synchronously call the editing delegate.
+final class TerminalDeletionRouter {
+  private var insideDeleteBackward = false
+
+  func deleteBackward(emit: () -> Void, performSystemDelete: () -> Void) {
+    insideDeleteBackward = true
+    defer { insideDeleteBackward = false }
+    emit()
+    performSystemDelete()
+  }
+
+  func emptyReplacement(emit: () -> Void) {
+    guard !insideDeleteBackward else { return }
+    emit()
+  }
+}

apps/mobile/modules/t3-terminal/scripts/test-terminal-deletion.swift

@@ -0,0 +1,28 @@
+import Foundation
+
+@main
+struct TerminalDeletionTest {
+  static func main() {
+    let router = TerminalDeletionRouter()
+    var sent = 0
+    let emit = { sent += 1 }
+
+    // Software keyboards may only send an empty replacement to the delegate.
+    router.emptyReplacement(emit: emit)
+    precondition(sent == 1)
+
+    // UIKit may also invoke that delegate from the subclass's super call.
+    router.deleteBackward(emit: emit, performSystemDelete: {
+      router.emptyReplacement(emit: emit)
+    })
+    precondition(sent == 2)
+
+    // A hardware-key callback can arrive without the editing delegate.
+    router.deleteBackward(emit: emit, performSystemDelete: {})
+    precondition(sent == 3)
+
+    // Ownership resets after the call, so later software-keyboard deletes work.
+    router.emptyReplacement(emit: emit)
+    precondition(sent == 4)
+  }
+}