[native_assets_cli] Fix snake casing in JSON

[dcharkes]

Closes: #2037
Closes: #2038

Fixes spelling in the JSON format:

• prefer-dynamic -> prefer_dynamic
• prefer-static -> prefer_static
• assetsForLinking -> assets_for_linking

PR changes

• pkgs/hook, pkgs/code_assets, and pkgs/data_assets

  • Introduces new schemas in the non-generated .schema.json files
  • Updates the generated schemas to pick up on the new spelling for assets_for_linking.
  • Adds test data for the new spelling.
  • Added JSON schema tests for the new spelling.

• package:native_assets_cli

  • Generated the syntax classes
  • Deal with version skew in the mapping between syntax classes and semantic API

Version skew between hooks and SDKs

• For [native_assets_cli] Rename assetsForLinking to assets_for_linking in JSON #2037

  • Backwards compatibility older SDKs: Also still emit assetsForLinking, instead of only assets_for_linking.
  • Backwards compatibility older hooks: Also still read assetsForLinking, instead of only assets_for_linking.

• For [native_assets_cli] Rename prefer-static to prefer_static in JSON #2038

  • Backwards compatibility older SDKs: Still read the casing with dashes.
  • Backwards compatibility older hooks: Irrelevant. Both Flutter and Dart only use dynamic.

[github-actions]

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// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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Files
pkgs/jni/lib/src/third_party/generated_bindings.dart
pkgs/objective_c/lib/src/ns_input_stream.dart

[mosuem]

(I think backwards compatibility makes the code less readable and is not needed on experimental features, but I know you disagree ;) )

[coveralls]

coverage: 86.019% (+0.003%) from 86.016%
when pulling eb0b868 on link-mode-preference-json
into 4073532 on main.