Add security auto remediation MVP

[EdgarPsda]

Summary

Adds the Security Auto Remediation MVP for DevSecOps Kit.

This PR introduces a functional vertical slice for automated remediation using Snyk findings, AI-generated/fallback patches, Git-safe application, validation, and re-scan verification.

What's included

• Added devsecops remediate
• Added Snyk remediation provider for HIGH/CRITICAL findings
• Added Maven dependency remediation fallback for pom.xml
• Added Spring Boot parent remediation support
• Added Git-safe remediation flow with branch creation and rollback
• Added baseline validation before remediation starts
• Added re-scan verification after each remediation attempt
• Added structured remediation engine foundation under internal/remediation
• Added PASS/WARN/FAIL scan evaluation model
• Hardened Semgrep execution and JSON parsing on Windows
• Added Git metadata-based versioning via ldflags
• Added Windows build.ps1

Validation

Tested with:

go test -vet=off ./...
.\build.ps1
.\devsecops.exe version

[github-actions]

🔐 DevSecOps Kit Security Summary

• Gitleaks: 0 leak(s)
• Trivy FS:
  • CRITICAL: 0
  • HIGH: 0
  • MEDIUM: 0
  • LOW: 0
• Semgrep: 9 finding(s)

Status: ✅ PASS