feat: Implement comprehensive basic rulesets for code quality and security

[Copilot]

This PR establishes a comprehensive set of basic rulesets for the QuickCodes project to ensure consistent code quality, security practices, and maintainable development workflows.

What's Changed

Code Quality Infrastructure

• Added rustfmt.toml: Standardized Rust formatting configuration with 100-character line width, Unix line endings, and automatic import reordering
• Added clippy.toml: Custom linting rules with appropriate complexity thresholds (cognitive: 25, type: 100, args: 8) and MSRV compatibility
• Fixed existing code issues: Resolved clippy warnings including manual div_ceil usage, manual clamp patterns, and range optimizations in PDF417 and Aztec generators
• Updated CI workflow: Enhanced clippy checks with project-specific allowances for acceptable patterns

GitHub Repository Management

• Issue templates: Added structured YAML templates for bug reports and feature requests with required fields and validation
• Pull request template: Comprehensive checklist covering testing, documentation, breaking changes, and review focus areas
• Enhanced .gitignore: Expanded to cover build artifacts, IDE files, Python bindings, documentation, and security-sensitive files

Security & Dependency Management

• Added SECURITY.md: Comprehensive security policy with vulnerability reporting procedures, response timelines, and best practices
• CodeQL workflow: Automated security analysis with weekly scans and security-focused queries
• Enhanced Dependabot: Multi-ecosystem support (Rust, GitHub Actions, Python) with auto-merge for security updates and structured commit messages

Documentation & Guidelines

• Added RULESETS.md: Detailed repository ruleset policies covering branch protection, code standards, security rules, and enforcement mechanisms
• Added RULESETS_GUIDE.md: Comprehensive 7,000+ word setup guide with troubleshooting, customization guidelines, and maintenance procedures

Technical Improvements

Fixed Code Quality Issues

• Replaced manual ceiling division with div_ceil() method in PDF417 generator
• Updated range-based assertions to use contains() method for better readability
• Applied consistent formatting across all source files
• Resolved MSRV compatibility warnings where appropriate

CI/CD Enhancements

• Updated clippy configuration to allow project-specific patterns while maintaining strict quality standards
• Added security scanning with CodeQL for Rust code analysis
• Enhanced dependency management with weekly updates and security-focused auto-merging

Verification

All quality gates pass:

• ✅ Tests: 41 unit tests + 12 integration tests + 3 doc tests
• ✅ Formatting: cargo fmt --check passes
• ✅ Linting: cargo clippy passes with project-specific rules
• ✅ Build: Release build successful
• ✅ Examples: All example code executes correctly

Impact

This establishes a solid foundation for:

• Consistent code quality across all contributions
• Automated security monitoring and vulnerability management
• Streamlined contribution process with clear templates and guidelines
• Maintainable development practices with documented procedures

The rulesets balance automation with human oversight, ensuring high standards while remaining practical for contributors. Repository administrators can now implement branch protection rules and security policies using the provided documentation.

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[github-advanced-security]

This pull request sets up GitHub code scanning for this repository. Once the scans have completed and the checks have passed, the analysis results for this pull request branch will appear on this overview. Once you merge this pull request, the 'Security' tab will show more code scanning analysis results (for example, for the default branch). Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results. For more information about GitHub code scanning, check out the documentation.