[CP-Beta] Add Flutter Errors for Migrating to AGP 9 (#179765 and #180018
) (#180038)
This is a manual cherry pick of #179765 and #180018 to beta. Combined into one CP PR because the second PR is a fix-forward.
### Issue Link:
What is the link to the issue this cherry-pick is addressing?
#179914
### Impact Description:
Impacted Users (Approximately who will hit this issue, ex. all Flutter devs, Windows developers, all end-customers, apps using X framework feature).
Flutter devs who ship to Android and are updating to AGP 9.0.0.
### Changelog Description:
Explain this cherry pick:
* In one line that is accessible to most Flutter developers.
* That describes the state prior to the fix.
* That includes which platforms are impacted.
See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples.
Added Flutter Errors to direct users to AGP 9 Migration Flutter docs when upgrading to AGP 9.0.0.
### Workaround:
Is there a workaround for this issue?
Currently, you can address the errors by looking through the comments at this issue [here](#175688) or reading Android AGP 9 preview docs [here](https://developer.android.com/build/releases/agp-preview).
### Risk:
What is the risk level of this cherry-pick?
### Test Coverage:
Are you confident that your fix is well-tested by automated tests?
### Validation Steps:
Create or use an existing Flutter app. Update to AGP 9.0.0. Address the errors as instructed in the Flutter error, then run `flutter run` on the project.

Bump engine version for 3.38.5 (#179743)
with bin/internal/last_engine_commit.sh > bin/internal/engine.version

Bump engine.version. (#179467)
We need to bump the engine version once more so that we're pointing at artifacts that were actually built for release (and therefore are signed.

Bump engine version for Flutter 3.38.4 stable hotfix. (#179424)

Bumpt the engine version after the dart version change (#179093)
bin/internal/last_engine_commit.sh > bin/internal/engine.version

3.38.3 bump engine sha (#178884)
part 2/2 of #178772

Update changelog with 3.38.2 cherrypicks (#178674)
https://github.com/flutter/flutter/commits/flutter-3.38-candidate.0?since=2025-11-14&until=2025-11-17

Bump `engine.version` (#178430)
Looks like DEPS changes require this bump.
**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

Update `engine.version` for 3.38 stable release (#178324)
To last commit merged, which was when the engine was last updated: cb467e3
**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

Update `engine.version` for 3.39 beta release (#178260)
Sets it to last commit: b9afb03
**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.