🔐 Update security tokens and documentation

[afonsoft]

• Update all GitHub Actions workflows to use standardized security tokens
• Configure CODECOV_TOKEN for coverage uploads in ci-build-test.yml
• Update SONAR_TOKEN to SONNAR_TOKEN in code-quality.yml and security-scan.yml
• Add comprehensive security tokens section to README.md
• Update CHANGELOG.md with security token changes
• Fix build status badge to point to correct workflow
• Document token configuration for developers

Tokens configured:

• CODECOV_TOKEN: For codecov coverage uploads
• NUGET_TOKEN: For NuGet.org publishing
• SONNAR_TOKEN: For SonarCloud analysis
• SNYK_TOKEN: Optional for Snyk security scans
• QODANA_TOKEN: Optional for Qodana code analysis

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions:

1. Does your submission pass tests?
2. Have you lint your code locally prior to submission?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud