chore(ci): Add concurrency to workflows for efficiency

[denver79]

Describe the issue

The Problem/Opportunity

Currently, when multiple commits are pushed to a Pull Request (PR), older workflows continue to run unnecessarily. This leads to inefficient use of CI/CD resources and longer wait times for developers to see test results.

The Suggestion

I propose adding the following concurrency block to most of the GitHub Actions workflows in the project:

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref }}
  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}

Benefits
Cost and Time Savings: This feature automatically cancels old and now-irrelevant workflows when a new commit is pushed to a PR. This directly reduces CI/CD runner minutes and costs.

Increased Efficiency: Developers will always see the test results for only the latest code. This prevents confusion and speeds up the development process.

Better Developer Experience: Wait times for test results are shortened, and the "Actions" history becomes cleaner.

I believe this small change will be a significant improvement to the project's CI/CD processes.

### Context

_No response_

### Steps to Reproduce or Propose

1. Add the proposed `concurrency` block to the relevant GitHub Actions workflow files.
2. Push a commit to a Pull Request, which will trigger a workflow run.
3. Before the first workflow is complete, push a second commit to the same Pull Request.
4. **Expected Change:** The first workflow run should be automatically canceled by GitHub. Only the workflow for the second, most recent commit should continue to run to completion.

[jytusdu]

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[jytusdu]

Zama very very good

[abdulmalikyar1]

This sounds like a reasonable improvement from a contributor point of view.

When iterating quickly on a PR, having older CI runs continue after newer commits are pushed can be wasteful and slows down feedback for the actual code being reviewed. Adding workflow-level concurrency with cancellation for non-main branches seems like a clean way to address this.

Using a group scoped to the workflow + head ref and cancelling in-progress runs outside main would:

• Reduce unnecessary CI usage
• Surface results for the latest commit faster
• Keep the Actions history easier to read for contributors

This would improve the overall contributor experience, especially for PRs that go through multiple iterations.