Add LLDB Init Instructions for Add to App (#12131)

Add instructions on how to manually add Flutter's LLDB Init File. This
is added to prevent crashes in debug mode on iOS 26.

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- [ ] This PR is marked as draft with an explanation if not meant to
land until a future stable release.
- [x] This PR doesn’t contain automatically generated corrections
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Author: vashworth

firebase.json

@@ -757,6 +757,7 @@
       { "source": "/to/integration-testing", "destination": "/cookbook/testing/integration/introduction", "type": 301 },
       { "source": "/to/intellij-setup", "destination": "/tools/android-studio#setup", "type": 301 },
       { "source": "/to/internationalization", "destination": "/ui/accessibility-and-internationalization/internationalization", "type": 301 },
+      { "source": "/to/ios-add-to-app-embed-setup", "destination": "/add-to-app/ios/project-setup#embed-a-flutter-module-in-your-ios-app", "type": 301 },
       { "source": "/to/ios-app-signing", "destination": "/deployment/ios#review-xcode-project-settings", "type": 301 },
       { "source": "/to/ios-create-flutter-engine", "destination": "/add-to-app/ios/add-flutter-screen#create-a-flutterengine", "type": 301 },
       { "source": "/to/ios-deploy", "destination": "/deployment/ios", "type": 301 },

src/_includes/docs/add-to-app/ios-project/embed-cocoapods.md

@@ -139,6 +139,48 @@ into your iOS app, complete the following procedure.
 
    1. Select **Product** > **Build** or press <kbd>Cmd</kbd> + <kbd>B</kbd>.
 
+#### Set LLDB Init File
+
+:::warning
+Set your scheme to use Flutter's LLDB Init File. Without this file, debugging
+on an iOS 26 or later device may crash.
+:::
+
+1. Generate Flutter LLDB files.
+
+   1. Within your flutter application, run the following:
+
+   ```console
+   flutter build ios --config-only
+   ```
+
+   This will generate the LLDB files in the `.ios/Flutter/ephemeral` directory.
+
+1. Set the LLDB Init File.
+
+   1. Go to **Product > Scheme > Edit Scheme**.
+
+   1. Select the **Run** section in the left side bar.
+
+   1. Set the **LLDB Init File** using the same relative path to your Flutter
+      application as you put in your Podfile in the **Update your Podfile**
+      section.
+
+      ```console
+      $(SRCROOT)/../my_flutter/.ios/Flutter/ephemeral/flutter_lldbinit
+      ```
+
+      If your scheme already has an **LLDB Init File**, you can add Flutter's
+      LLDB file to it. The path to Flutter's LLDB Init File must be relative
+      to the location of your project's LLDB Init File.
+
+      For example, if your LLDB file is located at `/path/to/MyApp/.lldbinit`,
+      you would add the following:
+
+      ```console
+      command source --relative-to-command-file "../my_flutter/.ios/Flutter/ephemeral/flutter_lldbinit"
+      ```
+
 [build-modes]: /testing/build-modes
 [CocoaPods getting started guide]: https://guides.cocoapods.org/using/using-cocoapods.html
 [Podfile target]: https://guides.cocoapods.org/syntax/podfile.html#target

src/_includes/docs/add-to-app/ios-project/link-and-embed.md

@@ -156,5 +156,46 @@ To embed your dynamic frameworks, complete the following procedure.
    1. Select **Product** <span aria-label="and then">></span>
       **Build** or press <kbd>Cmd</kbd> + <kbd>B</kbd>.
 
+#### Set LLDB Init File
+
+:::warning
+Set your scheme to use Flutter's LLDB Init File. Without this file, debugging
+on an iOS 26 or later device may crash.
+:::
+
+1. Generate Flutter LLDB files.
+
+   1. Within your flutter application, re-run `flutter build ios-framework` if
+      you haven't already:
+
+   ```console
+   $ flutter build ios-framework --output=/path/to/MyApp/Flutter/
+   ```
+
+   This will generate the LLDB files in the `/path/to/MyApp/Flutter/` directory.
+
+1. Set the LLDB Init File.
+
+   1. Go to **Product > Scheme > Edit Scheme**.
+
+   1. Select the **Run** section in the left side bar.
+
+   1. Set the **LLDB Init File** to the following:
+
+      ```console
+      $(PROJECT_DIR)/Flutter/flutter_lldbinit
+      ```
+
+      If your scheme already has an **LLDB Init File**, you can add Flutter's
+      LLDB file to it. The path to Flutter's LLDB Init File must be relative
+      to the location of your project's LLDB Init File.
+
+      For example, if your LLDB file is located at `/path/to/MyApp/.lldbinit`,
+      you would add the following:
+
+      ```console
+      command source --relative-to-command-file "Flutter/flutter_lldbinit"
+      ```
+
 [static or dynamic frameworks]: https://stackoverflow.com/questions/32591878/ios-is-it-a-static-or-a-dynamic-framework
 [static-framework]: https://developer.apple.com/library/archive/technotes/tn2435/_index.html