feat: update Docker Security Scan workflow with improved descriptions and input handling

[nookyo]

Docker Security Scan Workflow Enhancement

Overview

This pull request updates the GitHub Actions workflow for Docker image and source code security scanning with improved descriptions and more robust input parameter handling.

Key Changes

Workflow Metadata Improvements

• Renamed workflow: Vulnerability Scan → Docker Security Scan
• Removed redundant run-name to simplify the interface
• Cleaned up duplicate comments in the file header

Enhanced Parameter Descriptions

• image: Clarified description - "Docker image (for 'docker' target). By default ghcr.io/<owner>/<repo>:latest"
• only-high-critical: More descriptive - "Scan only HIGH + CRITICAL"
• trivy-scan: Clarified - "Run Trivy scan"
• grype-scan: Clarified - "Run Grype scan"

Improved Input Parameter Handling

• Added fallback values for critical parameters:
  • target: ${{ github.event.inputs.target || 'source' }}
  • image: ${{ github.event.inputs.image || '' }}
• Fixed reusable workflow reference: Netcracker → netcracker (lowercase)

Technical Improvements

• Removed redundant type: string for image parameter (default behavior)
• Enhanced file readability and structure

Benefits

1. Better UX: More intuitive parameter descriptions for workflow users
2. Reliability: Added fallback values to prevent workflow failures
3. Consistency: Aligned with naming conventions
4. Maintainability: Simplified structure without redundant code

Testing

The workflow has been tested with various input parameter combinations and demonstrates stable operation with improved edge case handling.

Impact

• No breaking changes
• Backward compatible
• Improved error handling
• Enhanced user experience

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This PR aims to enhance the quality and reliability of the security scanning process within the project's CI/CD pipeline.