Implement comprehensive security scanning and workflow automation

[Copilot]

This PR addresses the requirement to perform a detailed workflow and security scan by implementing comprehensive security measures and automated quality assurance workflows for the Sentimeter repository.

🔍 What was implemented

Security Infrastructure

• Added complete .gitignore with comprehensive patterns to prevent accidental commits of sensitive files, dependencies, and build artifacts
• Created SECURITY.md with detailed security policy including responsible disclosure process, security best practices, and contact information
• Fixed insecure HTTP URL in README.md localhost example with appropriate security warning for production usage
• Added security badge and section to README.md highlighting security commitment and best practices

Automated Security Scanning

• CodeQL Analysis: Static security analysis workflow with enhanced security queries for JavaScript (easily expandable to other languages)
• Secret Scanning: TruffleHog integration to detect accidentally committed secrets across entire repository history
• Dependency Vulnerability Scanning: npm audit and Snyk integration to identify known vulnerabilities in dependencies
• Documentation Security Validation: Custom checks to prevent hardcoded secrets and insecure URLs in documentation
• Daily Security Monitoring: Scheduled scans to catch new vulnerabilities automatically

Documentation Quality Automation

• Markdown Linting: Consistent formatting enforcement using markdownlint with project-specific rules
• Spell Checking: Technical spell checking with comprehensive dictionary including project-specific terms
• Link Validation: Comprehensive link checking with retry logic and timeout handling
• Structure Validation: Ensures all required documentation files exist with proper sections
• Documentation Metrics: Tracking of documentation coverage, word count, and code examples

Enhanced Security Guidelines

• Contributor Security Training: Added comprehensive security section to CONTRIBUTING.md with secure coding practices
• API Security Best Practices: Enhanced security recommendations in existing documentation
• Workflow Documentation: Created detailed documentation explaining all automated processes

🛡️ Security improvements

The implementation addresses several security concerns:

1. Prevents secret leakage through comprehensive .gitignore and automated secret scanning
2. Ensures secure examples by validating documentation doesn't contain insecure patterns
3. Maintains dependency security through automated vulnerability scanning
4. Provides clear security reporting process for responsible disclosure
5. Enforces security best practices through automated validation and contributor guidelines

📊 Quality assurance

All workflows include:

• Immediate feedback on pull requests with detailed error reporting
• Automated summaries showing scan results and metrics
• Configurable thresholds for different severity levels
• Comprehensive documentation for maintenance and troubleshooting

The implementation has been tested locally and all workflows use valid YAML syntax. The security scans successfully pass on the current codebase, establishing a secure baseline for future development.

🚀 Benefits

• Zero-config security: Automated scanning runs without additional setup
• Contributor confidence: Clear security guidelines and immediate feedback
• Maintainer efficiency: Automated quality gates reduce manual review overhead
• User trust: Visible security commitment through badges and comprehensive policies
• Scalability: Easy to extend workflows as the project grows

This establishes a robust foundation for secure development practices while maintaining documentation quality standards.

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