docs: expand OSV-Scanner comparison with concrete examples and structured sections

[sonukapoor]

The CVE Lite CLI vs OSV-Scanner section is thin. Expand it to match the Dependabot/npm audit depth with structured sections grounded in real scan data from the NestJS example repo.

Key points to cover:

• Both tools use OSV as the data source — why results still differ
• OSV-Scanner lists every individual CVE as a row (66 CVEs across 35 packages on NestJS); CVE Lite groups by package with fix commands
• No fix commands in OSV-Scanner output
• No direct vs transitive distinction or parent upgrade guidance
• Multi-ecosystem breadth vs JS/TS focus
• Where each tool has the edge and recommended combined approach