apple_sign_in_plugin

• Fixed dependency constraints on all platform packages and apple_sign_in_plugin_platform_interface (were ^0.0.1, which doesn't match any published version — only -dev prereleases exist — so pub get/pana resolution failed entirely). Now pinned to each package's actual published -dev version, matching the dependencies already used between the platform packages.
• Shortened pubspec.yaml's description to fit pub.dev's 60–180 character limit (was 231 characters, costing 10 pub points).

fix: bump apple_sign_in_plugin* to next dev version, fix publish/pub-…

• Trimmed pubspec.yaml topics to 5 (pub.dev's maximum); the previous 9-topic list blocked publishing entirely.

• Corrected to match pub.dev's actual last published version (1.2.6) — the repo's pubspec had drifted to 1.3.0 from an earlier commit that was bumped but never actually published — then patched.

• FIX(ci): melos release pipeline has never actually run — pin melos 6.x (#6).
• FEAT(infra): add Multi-OS test matrix (Linux, macOS, Windows) and comprehensive unit tests across all packages.
• FEAT(apple_sign_in_plugin): upgrade sign_in_with_apple to ^8.1.0 and bump version to 1.3.0 (#3).
• FEAT(packages): add dig_cli and apple_sign_in_plugin to monorepo.
• DOCS: standardize MIT license headers and holders across all monorepo packages.
• DOCS: standardize all README files to official Flutter packages format.

• Last version published to pub.dev before this rewrite.

• Build: Enforced strict dart format to satisfy CI/CD publishing requirements.
• Release: Final verified build.

• Fix: Applied dart format to example/lib/main.dart to ensure clean git state during publishing.
• Maintenance: Verified clean analysis and formatting for all files.

• Feature: Full export of sign_in_with_apple package (including widgets like SignInWithAppleButton).
• Feature: signInWithApple() returns AppleSignInResult with tokens for backend verification.
• CI/CD: Fully automated publishing via GitHub Actions with OIDC authentication.