PD-2262 - CVSS v4 Integration

[Yibaebi]

Title	Value
Type	Feature / Refactor
Ticket/Issue	PD-2262
Migrations	No
Data Migration Scripts	No
Seed DB	No
ENV vars change	No
Frontend (irene)	No
CLI (appknox-go)	No
On-premise (appknoxctl)	No
Translations (vulnerabilities)	No
Local testing	Pending
Staging testing	Pending
Documentation	None
Release notes	None
Version upgrade	Minor

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Changelog

1. Add CVSS v4 enums to ak_vendor/enums.py:
   • AttackRequirementsEnum (N/P)
   • VulnerableSubsequentSystemImpactEnum (H/L/N — shared across VC, VI, VA, SC, SI, SA)
   • UserInteractionV4Enum (N/P/A — replaces v3 N/R)
2. Refactor CVSSVersion class to inherit from str for easier comparisons
3. Update CVSS metrics handling in ak_vendor/report/report.py to support both v3 and v4 metric structures, including correct base severity extraction for v4 vectors
4. Update report template ak_vendor/templates/report_template.html to render CVSS v4 metrics table alongside legacy v3 metrics
5. Update cvss dependency to >=3.6 in pyproject.toml
6. Add Japanese translations for CVSS v4 metric labels in ak_vendor/locale/ja/LC_MESSAGES/django.po

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Dependent PRs

• mycroft — PD-2262-cvss-v4-integration-implementation
• sherlock — PD-2262-cvss-v4-sherlock-complete

[rajan262]

Looks good.