feat(sight): add unit tests for http endpoint and domain rule parsing

[Daydreamer-Li]

Description

Add unit tests covering the HTTP target configuration parsing logic:

• test_load_json_http_endpoint: validates endpoint parsing for :port and ip:port formats
• test_load_json_http_domain: validates domain rule parsing including exact match and wildcard patterns

Related Issue

closes #630

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional change)
• Performance improvement
• CI/CD or build changes

Scope

• sight (agentsight)

Checklist

• I have read the Contributing Guide
• My code follows the project's code style
• I have added tests that prove my fix is effective or that my feature works
• For sight: cargo test pass
• Lock files are up to date (Cargo.lock)

Testing

cargo test --lib — all tests pass including the two new test cases.