feat: enable full IPv6 support for ICMP, TCP, and HTTP probes

[abishekve]

Got it 👍 I’ll draft a PR description filled out for the changes you made (CIDR expansion, IPv6 + zone/scope handling, and new test cases).

Here’s a filled-in version of your template:

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Pull Request

📋 Description

• Added IPv6 CIDR expansion support in discovery and monitoring services.
• Preserved and handled zone/scope IDs for link-local IPv6 addresses (e.g., fe80::1%3).
• Added unit tests for CIDR expansion (IPv4 /24, /30, invalid CIDRs, and IPv6 /126valid for 120 -128).
• Ensured IPAddress.ScopeId is correctly parsed and retained when dealing with link-local addresses.

🔄 Type of Change

• 🐛 Bug fix
• 🚀 New feature
• 💥 Breaking change
• 📚 Documentation update
• 🔧 Code refactoring
• ⚡ Performance improvement
• 🛡️ Security enhancement
• 🧪 Test improvements

🧪 Testing

• Unit tests pass (IPv4 and IPv6 CIDR expansion, invalid CIDR handling, link-local with scope).
• [] Integration tests pass (discovery + probe service with IPv6).
• Manual testing completed for link-local probes (fe80::...%3).
• No existing tests were broken.

✅ Checklist

• [] My code follows the project's code style guidelines
• [] I have performed a self-review of my code
• [] I have commented my code, particularly in hard-to-understand areas
• [] I have made corresponding changes to the documentation (CIDR/IPv6 notes)
• [] My changes generate no new warnings
• [] I have added tests that prove my fix is effective or that my feature works
• [] New and existing unit tests pass locally with my changes

🔍 Code Quality

• [] Code has been formatted using project standards
• [] No hardcoded secrets or sensitive data included
• [] Error handling is appropriate
• [] Logging is appropriate (no sensitive data logged)