Bump analyzer to 9

[tenhobi]

Fixes #251

[Copilot]

Pull request overview

This PR updates the analyzer dependency from version 8 to version 9, addressing issue #251 which requested analyzer 9.0.0 support for compatibility with json_serializable 6.11.3. The changes involve migrating from the deprecated analyzer element2 API to the current element API, along with SDK and dependency updates.

Key Changes:

• Migrated from analyzer's deprecated element2 API to the current element API throughout the codebase
• Updated analyzer dependency from >=8.1.1 <9.0.0 to ^9.0.0 and SDK from ^3.8.0 to ^3.9.0
• Refactored test fixtures to use with EquatableMixin instead of extends Equatable and added AAA (Arrange-Act-Assert) structure to tests

Reviewed changes

Copilot reviewed 96 out of 96 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pubspec.yaml files	Updated SDK to ^3.9.0, analyzer to ^9.0.0, melos to ^7.3.0, netglade_analysis to ^19.0.0
lib/src/**/*.dart	Migrated from deprecated element2 API (element2, element3, name3, library2, etc.) to element API (element, name, library, etc.)
test fixtures	Changed from extends Equatable to with EquatableMixin pattern
test files	Added AAA comments, numeric separators, and formatting improvements
.fvmrc	Removed updateVscodeSettings configuration

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.