docs: expand Socket CLI comparison with concrete examples and structured sections

[sonukapoor]

The CVE Lite CLI vs Socket CLI section is thin. Expand it to match the Dependabot/npm audit depth.

Socket requires a paid account for full scans so direct comparison data is limited, but the structural differences are well-documented:

• Socket goes beyond CVEs into supply-chain risk (malware, typosquatting, suspicious maintainers, license issues)
• Different threat model: not just "is this version vulnerable" but "is this package trustworthy"
• CVE Lite and Socket are largely complementary rather than competitive
• Where each tool has the edge and recommended combined approach