feat: use grantbirki/comment for commenting and update grading job in step 3

[FidelusAleksander]

Summary

Changes

Closes:

Task list

• For workflow changes, I have verified the Actions workflows function as expected.
• For content changes, I have reviewed the style guide.

[Copilot]

Pull Request Overview

This PR refactors how issue comments are posted by replacing inline gh issue comment calls with the GrantBirki/comment action, updates exercise-toolkit versions, and tightens the step-3 validation logic.

• Swap out CLI-based commenting for GrantBirki/comment@v2.1.1 across workflows
• Upgrade all skills/exercise-toolkit workflow references to v0.7.0 (except one unintended v0.5.0)
• Refactor Step 3 to use action-keyphrase-checker and a shell check for PR title and description

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/0-start-exercise.yml	Bumped toolkit to v0.7.0; switched to comment action; updated env
.github/workflows/1-create-a-branch.yml	Bumped toolkit to v0.7.0; switched to comment action; updated env
.github/workflows/2-commit-a-file.yml	Added path filter; bumped toolkit; switched to comment action
.github/workflows/3-open-a-pull-request.yml	Refactored comment steps; added find-comment; tightened checks
.github/workflows/4-merge-your-pull-request.yml	Swapped in comment action; added disable workflow; bumped finish-exercise version
.github/steps/x-review.md	Updated link for additional exercises

Comments suppressed due to low confidence (4)

.github/workflows/4-merge-your-pull-request.yml:25

• This reference is using @v0.5.0 while all other steps use v0.7.0. It may lead to incompatibilities; please bump to v0.7.0 for consistency.

    uses: skills/exercise-toolkit/.github/workflows/find-exercise-issue.yml@v0.5.0

.github/workflows/3-open-a-pull-request.yml:119

• GitHub Actions expressions don't support wildcards like steps.*.outcome. Consider explicitly checking each step’s outcome or gather them into an array before using contains.

        if: contains(steps.*.outcome, 'failure')

.github/workflows/4-merge-your-pull-request.yml:23

• The find_exercise job no longer has an if condition to guard against running in template repos or on unintended branches. You may want to re-add the same if: !github.event.repository.is_template filter used elsewhere.

  find_exercise:

.github/steps/x-review.md:27

• [nitpick] Please verify the updated link https://learn.github.com/skills is correct and resolves properly; the previous URL format was skills.github.com.

- [Take another GitHub Skills exercise](https://learn.github.com/skills).