Compare total GSC clicks with total GA4 organic sessions to detect tracking gaps.

Fetches aggregate GSC clicks (no page dimension) and sums all organic sessions from GA4. The ratio ga4_sessions / gsc_clicks indicates tracking health:

• "no_gsc_data" : zero GSC clicks (ratio is None, nothing to compare)

• "tracking_gap" : ratio < 0.6 (GA4 records far fewer sessions than GSC clicks)

• "filter_issue" : ratio > 1.3 (GA4 records more sessions than GSC clicks)

• "healthy" : 0.6 <= ratio <= 1.3

Boundaries 0.6 and 1.3 are inclusive of the healthy range (strict < and >). GA4 is queried with limit=10000 to avoid under-counting sessions on large sites.

Join GSC and GA4 data at the page level and rank by opportunity score.

GSC rows are fetched with dimensions=["page"] (already aggregated per page). GA4 organic landing pages are fetched with a high limit to avoid truncation. Pages are joined on _normalize_url. Pages that appear in only one source get None for the missing fields.

opportunity_score = log10(impressions+1)10 + engagement_rate100 + log10(conversions+1)*20

engagement_rate is derived as engaged_sessions/sessions (GA4 native formula) because ga4_organic_landing_pages does not expose it directly.

Results are sorted by opportunity_score descending, truncated to limit.