Add PR review agent - rebased

[Unshure]

Needed to rebase the original pr, but since @mehtarac is away for a bit, im moving these changes to my repo so I can get them merged.

Original pr: #399

Description

This PR adds an Agent as a github action workflow. This agent can be used following a /strands review command, which triggers the action to start the review process. During the review:

1. Agent sets the the review environment reading the PR description, current branch, and identifies the type of change.
2. Identifies the linked issue, checks for existing review comments and uses a new tool, get_pr_files to review changed files and scope.
3. Reviews repo guidelines from CONTRIBUTING.md and AGENTS.md
4. Does a code analysis for

• File and directory strucuture, naming conventions, and breaking changes
• Language best practices
• Testing review
• Documentation review

5. Generates review comments
6. Posts review comments

Related Issues

#1

Documentation PR

N/A

Type of Change

New feature

Testing

How have you tested the change?
Tested in forked repo on a sample PR: mehtarac#1

• I ran npm run check

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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