Improves CI workflow with coverage and build steps

[MelbourneDeveloper]

TLDR;

Refactors the CI workflow to improve reliability and ensure code quality by adding test coverage checks, spell checks, and dedicated build steps for all packages and examples.

What Does This Do?

This change aims to enhance the CI pipeline, adding new checks and improving existing ones. It introduces test coverage verification to ensure code quality, spell checking to maintain documentation standards, and dedicated build steps to catch integration issues early.

Brief Details?

• Introduces a new GitHub action for setup, installing Dart, Node.js, and caching dependencies.
• Adds a GitHub action to run tests with coverage and enforce a minimum coverage percentage.
• Refactors the CI workflow to include spell checking, formatting, and static analysis.
• Implements separate jobs for setting up the environment, testing packages, testing examples, and building all targets.
• Updates publish workflows to check for package availability before publishing dependent packages.
• Fixes an issue in the publish workflow by switching the package to be published in tier 1

How Do The Tests Prove The Change Works?

The changes introduce test coverage checks for both packages and examples. The workflow will fail if the coverage falls below a predefined threshold (80% by default), ensuring that tests adequately cover the codebase. Additionally, the build step ensures that all packages and examples can be built successfully, verifying integration.