Expand URL and network safety regression matrix

[LarryLemonBot]

Roadmap item for hardening scanner boundaries.

Goal:
Broaden regression coverage for SSRF and accidental data exposure risks.

Candidate cases:

• DNS answers resolving to private, loopback, link-local, multicast, and reserved ranges
• credentialed URLs
• redirects to blocked hosts
• suspicious query keys that should be sanitized from artifacts
• malformed URLs and unusual schemes

Acceptance criteria:

• Tests remain offline or use controlled local fixtures.
• Failures are explicit and claim-bounded.
• No new private endpoint probing is introduced.