feat: Add PyPI Inspector link for remote PyPI scans with issues

[xxiaoxiong]

Description

This PR implements the feature requested in #67.

When scanning a remote PyPI package and issues are found, GuardDog now displays a link to PyPI Inspector for easier investigation.

Changes

• cli.py: Added is_remote, ecosystem, and scanned_version fields to scan results for remote scans
• human_readable.py: Display PyPI Inspector link when:
  • Scanning a remote PyPI package (not local files)
  • At least one issue is found
  • Version information is available
• test_human_readable.py: Added 5 test cases to verify:
  • Link is shown for remote PyPI scans with issues
  • Link is NOT shown for local scans
  • Link is NOT shown when no issues found
  • Link is NOT shown for other ecosystems (npm, etc.)
  • Link is NOT shown when version is None

Example Output

Found 2 potentially malicious indicators in requests

some-rule: found suspicious behavior

For more details, see: https://inspector.pypi.io/project/requests/2.28.1

Testing

All new tests pass. The implementation follows the existing code style and patterns.

Fixes #67