Update finding by github username prod (step 4)

[lukaszgryglicki]

cc @mlehotskylf @ahmedomosanya

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[Copilot]

Pull Request Overview

This PR adds validation for GitHub usernames before attempting to lookup users by login name. The changes introduce a validation function to check if a name conforms to GitHub's username requirements (3-39 characters, alphanumeric and hyphens only, no leading/trailing hyphens, no consecutive hyphens) before making API calls.

• Adds GitHub username validation regex patterns in both Python and Go backends
• Implements validation functions to check username format before API lookups
• Updates documentation to clarify co-author resolution process
• Refactors AWS log analysis utilities for better modularity

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
cla-backend/cla/models/github_models.py	Adds GitHub username regex pattern and validation function
cla-backend-go/github/github_repository.go	Implements GitHub username validation in Go
CO_AUTHORS.md	Updates documentation with validation details and troubleshooting
utils/count_apis.sh	New utility script for counting API usage patterns
utils/calculate_api_stats.sh	New script for calculating API statistics across regions
utils/search_aws_logs.sh	Refactors to use new count_apis.sh utility
utils/search_aws_log_group.sh	Adds example usage comments
tests/functional/README.md	Adds SSH-compatible test running command

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