Work towards flutter/flutter#187899

Fixes flutter/flutter#188406

## Pre-Review Checklist

This PR introduces optional Native Interop to Pigeon, enabling direct communication between Dart and native code without the overhead of traditional MethodChannel serialization. It leverages FFI (Foreign Function Interface) for Swift (iOS/macOS) and JNI (Java Native Interface) for Kotlin (Android).

This represents a significant architectural shift, moving from message-based passing to direct memory sharing and function calls. It also updates the concurrency model for asynchronous methods, moving from completion handlers/callbacks to modern language features: async/await in Swift and Coroutines in Kotlin.

Generators Covered

Swift Generator: Updated to support FFI bindings and async/await for asynchronous methods.
Kotlin Generator: Updated to support JNI bindings and Kotlin Coroutines for asynchronous methods.
Dart Generator: Updated to handle the generated interop bindings on the Dart side.

What's In Scope

1. Infrastructure: Added core support for useFfi and useJni options.
2. Automation: Implemented multi-step generation flows that automatically invoke jnigen and ffigen to produce final bindings.
3. Config Generation: Added jnigen_config_generator.dart and ffigen_config_generator.dart to generate the necessary configuration files for the external tools.
4. Documentation: Added a detailed native_interop_guide.md explaining prerequisites, setup, and usage.
Tests: Added ni_tests.dart and associated generated files and integration tests to verify the feature.

What's Out of Scope

1. Other Languages: This PR specifically targets Swift and Kotlin for the Native Interop feature. Support for Objective-C, C++, and GObject is not included in this interop implementation, and may not be in the future.
2. Performance Optimization for Complex Classes: As noted in the guide, there is a known performance regression when transferring complex classes with many fields compared to MethodChannel Pigeon. This PR delivers the functional infrastructure, but optimizing this specific case is left for follow-up work.
3. Non-instant released data. Currently all data that is sent over host or flutter api surfaces is converted to the correct shape and type for the language it is moving toward and the data created in the other language is then discarded. This presents some inefficiencies and potential workflows that are not yet available.

work toward flutter/flutter#182230
design doc flutter/flutter#181430

…2716)

Null safety when ContentResolver cannot open a stream. 

Copied from closed: #12683

Fixes: #191989

## Pre-Review Checklist

…iptions (#11551)

Fixes a potential cause of  flutter/flutter#181530

Quite a few IAP bugs seem to be surrounding stale data, so expose the expiration date directly to have to avoid doing local receipt shenanigans. 

## Pre-Review Checklist

…te (#12608)

This PR adds the `keyboardInputFormatters` method to `CalendarDelegate`.

Previously, date input was strictly coupled to `MaterialLocalizations`. This change allows developers to provide a list of `TextInputFormatter`s via a custom `CalendarDelegate` to enforce specific input masks (e.g., dd/MM/yyyy) or restrict character entry in date pickers (`showDatePicker`, `showDateRangePicker`, and `InputDatePickerFormField`).

Fixes flutter/flutter#83302
Fixes flutter/flutter#97134 
Fixes flutter/flutter#62401
Fixes flutter/flutter#181043
Fixes flutter/flutter#115151
Fixes flutter/flutter#191639
Fixes partially flutter/flutter#150611

Port of flutter/flutter#181105

## Pre-Review Checklist

**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.

[^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.

The previous sync back for 1.1.1 is landed after the 1.2.0 batch release is triggered. so 1.2.0 went out as if 1.1.1 is not there, you can see the changelog of 1.2.0 swallow the change log item from 1.1.1, while the 1.1.1's section is completely missing
<img width="1371" height="728" alt="image" src="https://github.com/user-attachments/assets/0278041c-1fa2-49aa-8cba-9bedd9db9c00" />

This pr cleans it up and restore the correct change log order 

## Pre-Review Checklist

**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.

[^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.

Null safety when ContentResolver cannot open a stream.

Copied from closed: #12682

Fixes: flutter/flutter#191988

## Pre-Review Checklist

adds main actor annotation to async flutter api methods in swift.

fixes flutter/flutter#192199