Feat/dart precompiled binary

.gitignore

@@ -3,6 +3,7 @@ target
 !example.config.toml
 *.sqlite
 Cargo.lock
+
 .vscode
 mutants.out*
 *.ikm

payjoin-ffi/dart/.gitignore

@@ -13,3 +13,7 @@ doc/api/
 # Auto-generated bindings
 lib/payjoin.dart
 lib/bitcoin.dart
+
+# Auto-generated precompiled binaries
+precompiled_build/
+precompiled_upload/

payjoin-ffi/dart/README.md

@@ -2,6 +2,48 @@
 
 Welcome to the Dart language bindings for the [Payjoin Dev Kit](https://payjoindevkit.org/)!
 
+## Using the bindings in your app
+
+Declare the package as a dependency just like any other Dart package. When developing against the repo directly, point at the local path and let `flutter pub get` (or `dart pub get`) run the build hook:
+
+```yaml
+dependencies:
+  payjoin:
+    path: ../rust-payjoin/payjoin-ffi/dart
+```
+
+The `hook/build.dart` script drives `native_toolchain_rust` (plus the precompiled-binaries helper) so that `flutter pub get` downloads the verified binaries when available or builds the native crate locally on demand.
+
+If you prefer to inspect or regenerate `payjoin.dart` manually, run the binder script from the `payjoin-ffi/dart` directory:
+
+```bash
+bash ./scripts/generate_bindings.sh
+```
+
+This produces `lib/payjoin.dart` and the native artifacts under `target/`. These files are not tracked in the repository, so you should regenerate them locally whenever the Rust API changes.
+
+## Precompiled binaries
+
+This package supports downloading signed precompiled binaries or building locally via Dart's Native Assets hook.
+If precompiled binaries are attempted but unavailable or verification fails, it falls back to building from source.
+
+### pubspec.yaml configuration
+
+In your app's `pubspec.yaml`, add the `payjoin` section at the top level (next to `dependencies`), like:
+
+```yaml
+payjoin:
+  precompiled_binaries:
+    mode: auto # auto | always | never
+```
+
+`mode` controls when the precompiled path is used:
+- `auto` prefers local builds if Rust toolchain is detected, otherwise uses precompiled binaries
+- `always` requires precompiled binaries and skips local builds
+- `never` always builds from source via the build hook
+
+If your tooling must rely on the signed GitHub releases, set `mode: always` and configure `artifact_host`/`public_key` to point at the published assets so `PrecompiledBuilder` can download the `precompiled_<crateHash>` bundles (macOS/iOS + Android builds are published via `.github/workflows/payjoin-dart-precompile-binaries.yml`).
+
 ## Running Tests
 
 Follow these steps to clone the repository and run the tests.
@@ -16,3 +58,5 @@ bash ./scripts/generate_bindings.sh
 # Run all tests
 dart test
 ```
+
+Maintainers: see `docs/precompiled_binaries.md` for CI details, manual release steps, and configuration.

payjoin-ffi/dart/native/.gitignore

@@ -0,0 +1 @@
+!Cargo.lock