feat(pipeline): add numeric comparison mode to sort step

[Astro-Han]

Description

Add numeric: true option to the pipeline sort step so string-encoded numbers are compared numerically instead of lexicographically.

When APIs return numeric values as strings (e.g. "quoteVolume": "1234567.89"), the sort step uses lexicographic ordering, causing "99" to rank above "1000". With numeric: true, values are converted via Number() with a Number.isFinite() guard before comparison.

- sort:
    by: quoteVolume
    order: desc
    numeric: true

Closes #304

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🌐 New site adapter
• 📝 Documentation
• ♻️ Refactor
• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful

Screenshots / Output

 PASS  src/pipeline/transform.test.ts (21 tests)

 ✓ stepSort > sorts string-encoded numbers numerically with numeric: true
 ✓ stepSort > sorts string-encoded numbers lexicographically without numeric
 ✓ stepSort > treats non-numeric values as 0 when numeric: true
 ✓ stepSort > handles "0" and negative numbers correctly with numeric: true
 ✓ stepSort > treats missing fields as 0 when numeric: true