feat: GA4 monetization/ad revenue reports

[saraichinwag]

Summary

Leverage GA4's built-in monetization reports as a partial solution for ad revenue visibility when direct Mediavine API access isn't available.

Context

Mediavine doesn't have a public API (#757). GA4 has some ad revenue data that could be useful:

• Ad revenue — estimated from AdSense/other ad integrations
• Publisher ads — impressions, clicks, revenue
• E-commerce — if SMI sales are tracked as events

GA4 Metrics Available

From GA4 Data API:

• totalAdRevenue — estimated ad revenue
• publisherAdClicks — ad clicks
• publisherAdImpressions — ad impressions
• buyerTaxonomy — for e-commerce attribution

Proposed Enhancement to datamachine/get-ga4-analytics

Add metrics parameter that includes:

{
  "metrics": ["sessions", "pageviews", "adRevenue", "adImpressions"],
  "dimensions": ["pagePath", "date"],
  "period": "30d"
}

Output:

{
  "success": true,
  "rows": [
    {
      "page_path": "/spiritual-meaning-crows/",
      "sessions": 1500,
      "pageviews": 2100,
      "ad_revenue": 12.34,
      "ad_impressions": 45000,
      "rpm": 8.23
    }
  ]
}

Limitations

• GA4 ad revenue is estimated, not actual Mediavine payments
• May not match Mediavine dashboard exactly
• Useful for trends and relative comparison, not exact accounting

Priority

Medium — useful for revenue visibility, but not a complete solution. Better than nothing if Mediavine scraping is too fragile.

Related

• RFC: Mediavine/Journey ad revenue visibility #757 — Mediavine revenue RFC
• feat: Revenue attribution — traffic source → income mapping #758 — Revenue attribution