Repository: flutter
Issue: [ios][add2app] `Flutter.podspec` is missing after running `flutter build ios-framework`
Labels: platform-ios,tool,a: existing-apps,t: xcode,has reproducible steps,P2,team-ios,triaged-ios,found in release: 3.27,found in release: 3.28

### Steps to reproduce

I'm following Add to app guideline for iOS, the last option[Use frameworks and CocoaPods](https://docs.flutter.dev/add-to-app/ios/project-setup#89-tab-panel) 

After I run command `flutter build ios-framework`, all frameworks are exported successfully, but in step `Add Flutter engine to your Podfile`, docs stated that I need to update Podfile with :

```
pod 'Flutter', :podspec => '/path/to/MyApp/Flutter/[build mode]/Flutter.podspec'
```
I looked for `Flutter.podspec` in all 3 build modes: Debug, Profile and Release but could not see it.

This seems to be happened in the past with https://github.com/flutter/flutter/issues/55095?

### Expected results

`Flutter.podspec` should be exported as mentioned in the docs

### Actual results

`Flutter.podspec` is missing 

### Code sample

https://github.com/huycozy/reproduce_issue_ios_native_addtoapp_optionC


### Screenshots or Video

<details open>
<summary>Screenshots / Video demonstration</summary>

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</details>


### Logs

<details open><summary>Logs</summary>

```console
[Paste your logs here]
```

</details>


### Flutter Doctor output

<details open>
<summary>flutter doctor -v (stable and master)</summary>

```console
[✓] Flutter (Channel stable, 3.27.2, on macOS 15.2 24C101 darwin-x64, locale en-VN)
    • Flutter version 3.27.2 on channel stable at /Users/huynq/Documents/GitHub/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 68415ad1d9 (9 hours ago), 2025-01-13 10:22:03 -0800
    • Engine revision e672b006cb
    • Dart version 3.6.1
    • DevTools version 2.40.2

[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
    • Android SDK at /Users/huynq/Library/Android/sdk
    • Platform android-35, build-tools 35.0.0
    • ANDROID_SDK_ROOT = /Users/huynq/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 16.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16C5032a
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2024.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /Applications/Android Studio.app
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)

[✓] IntelliJ IDEA Community Edition (version 2024.2.3)
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin version 81.1.3
    • Dart plugin version 242.22855.32

[✓] VS Code (version 1.96.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.102.0

[✓] Connected device (3 available)
    • Pixel 7 (mobile) • 2B171FDH20084L • android-arm64  • Android 15 (API 35)
    • macOS (desktop)  • macos          • darwin-x64     • macOS 15.2 24C101 darwin-x64
    • Chrome (web)     • chrome         • web-javascript • Google Chrome 131.0.6778.265

[✓] Network resources
    • All expected network resources are available.

• No issues found!
```

```console
[!] Flutter (Channel master, 3.28.0-2.0.pre.38724, on macOS 15.2 24C101 darwin-x64, locale en-VN) [4.2s]
    • Flutter version 3.28.0-2.0.pre.38724 on channel master at /Users/huynq/Documents/GitHub/flutter_master
    ! Warning: `flutter` on your path resolves to /Users/huynq/Documents/GitHub/flutter/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/huynq/Documents/GitHub/flutter_master. Consider adding /Users/huynq/Documents/GitHub/flutter_master/bin to the front of your path.
    ! Warning: `dart` on your path resolves to /Users/huynq/Documents/GitHub/flutter/bin/dart, which is not inside your current Flutter SDK checkout at /Users/huynq/Documents/GitHub/flutter_master. Consider adding /Users/huynq/Documents/GitHub/flutter_master/bin to the front of your path.
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 1b0441c18a (2 hours ago), 2025-01-13 17:29:08 -0800
    • Engine revision 1b0441c18a
    • Dart version 3.7.0 (build 3.7.0-312.0.dev)
    • DevTools version 2.42.0
    • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades.

[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [5.7s]
    • Android SDK at /Users/huynq/Library/Android/sdk
    • Platform android-35, build-tools 35.0.0
    • ANDROID_SDK_ROOT = /Users/huynq/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 16.2) [2.6s]
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Build 16C5032a
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web [259ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2024.2) [257ms]
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • android-studio-dir = /Applications/Android Studio.app
    • Java version OpenJDK Runtime Environment (build 21.0.4+-12422083-b607.1)

[✓] IntelliJ IDEA Community Edition (version 2024.2.3) [248ms]
    • IntelliJ at /Applications/IntelliJ IDEA CE.app
    • Flutter plugin version 81.1.3
    • Dart plugin version 242.22855.32

[✓] VS Code (version 1.96.2) [30ms]
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.102.0

[✓] Connected device (3 available) [7.7s]
    • Pixel 7 (mobile) • 2B171FDH20084L • android-arm64  • Android 15 (API 35)
    • macOS (desktop)  • macos          • darwin-x64     • macOS 15.2 24C101 darwin-x64
    • Chrome (web)     • chrome         • web-javascript • Google Chrome 131.0.6778.265

[✓] Network resources [509ms]
    • All expected network resources are available.

! Doctor found issues in 1 category.

```
</details>