[ffigen] Dart API feedback 2026-08-28 #3595

I'm really happy with our new API! I can only think of some final nits, no actual refactorings! 🥳

• Migrate all existing yaml files in the repo.

• class ExternalVersions is undocumented.
  It's actually somewhat weird that these refer to specially recognized APIs from Apple. But it's probably fine.
  If we ever introduce Dart conditional compilation, we'd split the generated code across different OS versions, and probably completely remove this config option. This config option only makes sense when there's no conditional compilation.

• Enable public api docs lint.

linter:
  rules:
    - public_member_api_docs

• Cpp mark the class getter and constructor param @experimental.

Code Style Nits

(These are our samples we direct users to from the docs. So I care about their style.)

pkgs/code_assets/example/host_name/tool/ffigen.dart

• Nit: I'd inline visitors so that the generators are complete. (Because we also repeat the DartOutput with a slightly different url)

pkgs/code_assets/example/mini_audio/tool/ffigen.dart

• multi-line expressions are harder to read than defining an extra const:

          node.isIncluded = {
            'ma_engine_init',
            'ma_engine_play_sound',
            'ma_engine_uninit',
          }.contains(node.name);

->

          const include = {
            'ma_engine_init',
            'ma_engine_play_sound',
            'ma_engine_uninit',
          };
          node.isIncluded = include.contains(node.name);

Context:

• [ffigen] ☂️ Dart API #2556