[quick_actions] Switch to Kotlin Pigeon

[stuartmorgan-g]

Replaces the Java Pigeon generator with the Kotlin Pigeon generator, and adjusts the project accordingly:

• Adds Kotlin build setings to Gradle.
• Updates API signatures for Kotlin/Java differences.
• Adds generic Java/Kotlin compat shim to create Result objects from Java, since those haven't been added to the Pigeon generator yet.

Part of flutter/flutter#158287

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

Footnotes

1. Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩²

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

[stuartmorgan-g]

test-exempt: code refactor with no semantic change

[gemini-code-assist]

Code Review

This pull request migrates the quick_actions_android package to use Kotlin Pigeon for its internal implementation. The changes involve updating the build configuration to support Kotlin, replacing Java-generated Pigeon files with Kotlin versions, and refactoring the Android plugin implementation to align with the new API. Feedback points out an invalid Kotlin version in the build script and an unsafe unchecked cast in the utility code.

[gemini-code-assist]

This unchecked cast from Any to a functional type is unsafe and could lead to a ClassCastException at runtime. Furthermore, the success method (lines 24-27) appears to be unused in this pull request. Consider removing unused code to keep the shim minimal.