feat(scanner): AZ-NET-016 — Load Balancer Has No Backend Pool Configured

[aav-wh]

What does this PR do?

Adds AZ-NET-016 scanner rule to detect Azure load balancers with no backend pool configured, which are either misconfigured or leftover resources from decommissioned workloads.

Type of change

• New scan rule
• Remediation playbook
• Compliance mapping

Rule details

• Rule ID: AZ-NET-016
• Severity: LOW
• Category: Network
• Frameworks mapped: CIS 9.1 / NIST CM-7 / ISO A.13.1.1 / SOC 2 CC8.1

Testing

• Returns correct JSON output
• All seven CI checks pass
• No hardcoded credentials or secrets

Related issue

Closes #107

Checklist

• My code follows the rule template in CONTRIBUTING.md
• I added or updated the matching CLI playbook
• I added or updated all four compliance framework mappings
• I have not committed any real Azure credentials
• My branch name follows the convention: feat/description