Support build 5 with Freezed and build_runner 2.17.1 #1378

Describe the bug

freezed 4.0.2 and build_runner 2.17.1 cannot resolve together: Freezed requires build >=3.0.0 <5.0.0, while the runner requires build >=5.0.0 <5.1.0.

Tested independently with Dart 3.13.5 on Windows. The minimal case intentionally includes only Freezed and the runner, isolating this constraint from other generators. Resolution stops before code generation; this is not proof of a Freezed source/API incompatibility.

To reproduce

Create this pubspec.yaml in an empty directory, then run dart pub get:

name: build5_freezed_repro
publish_to: none
environment:
  sdk: ^3.13.5
dev_dependencies:
  build_runner: ^2.17.1
  freezed: 4.0.2

Actual result (exit code 1):

Because freezed >=3.2.3 depends on build >=3.0.0 <5.0.0 and build_runner >=2.17.1 depends on build >=5.0.0 <5.1.0, freezed >=3.2.3 is incompatible with build_runner >=2.17.1.
So, because build5_freezed_repro depends on both build_runner ^2.17.1 and freezed 4.0.2, version solving failed.

Expected behavior

Please validate Freezed with build 5 and publish a supported dependency range that permits the current stable build_runner, if compatible.

The build_runner changelog explains its build 5 requirement. The current Freezed manifest excludes that version. The earlier build 3/4 request #1299 is closed and concerns the preceding transition.

No dependency overrides were used.