Narrow tracker-mapping confidence to attribution

The agent returned a single confidence that conflated two unrelated
judgments: whether an artifact is a meaningful web tracker and which
vendor set it. The prompt's tracker-worthiness skepticism drove the
number down for extension state like __darkreader__wasEnabledForHost,
pushing it below the gate and dropping the attribution entirely, so a
clearly-named vendor never reached the catalog.

Rename the agent field to ThirdPartyConfidence and scope it to the
attribution alone. The identify gate now checks that a vendor is named
with sufficient confidence; on success the catalog row is stored at a
fixed agent confidence like the other heuristic signals, and on failure
the unmatched fallback still records the pattern with no third party.

The stored pattern confidence was only used for ordering and as agent
context, never as a gate, so a separate LLM-provided number is dropped
rather than split out.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/cookiebanner/tracker_mapping_worker.go

@@ -515,33 +515,29 @@ func (h *trackerMappingHandler) identifyWithAgent(
 
 	identification := result.Output
 
-	if identification.Confidence < agentConfidenceThreshold {
+	// The agent's confidence gauges the attribution (who set the
+	// tracker), not whether the artifact is a meaningful tracker. Without
+	// a confident vendor there is nothing to catalog here; the unmatched
+	// fallback records the pattern with no third party instead.
+	if identification.ThirdPartyName == "" || identification.ThirdPartyConfidence < agentThirdPartyConfidenceThreshold {
 		h.logger.InfoCtx(
 			ctx,
-			"agent identification below confidence threshold",
+			"agent third-party attribution below confidence threshold",
 			log.String("pattern", tp.Pattern),
-			log.Float64("confidence", identification.Confidence),
+			log.Float64("third_party_confidence", identification.ThirdPartyConfidence),
 		)
 
 		return nil, nil
 	}
 
-	confidence := float32(identification.Confidence)
-	if confidence > agentMaxPatternConfidence {
-		confidence = agentMaxPatternConfidence
-	}
-
-	var commonThirdPartyID *gid.GID
-	if identification.ThirdPartyName != "" {
-		commonThirdPartyID, err = h.resolveOrCreateCommonThirdParty(
-			ctx,
-			tx,
-			identification,
-			domains,
-		)
-		if err != nil {
-			return nil, fmt.Errorf("cannot resolve or create common third party: %w", err)
-		}
+	commonThirdPartyID, err := h.resolveOrCreateCommonThirdParty(
+		ctx,
+		tx,
+		identification,
+		domains,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("cannot resolve or create common third party: %w", err)
 	}
 
 	now := time.Now()
@@ -552,7 +548,7 @@ func (h *trackerMappingHandler) identifyWithAgent(
 		Pattern:            tp.Pattern,
 		MatchType:          tp.MatchType,
 		MaxAgeSeconds:      tp.MaxAgeSeconds,
-		Confidence:         confidence,
+		Confidence:         agentSourceConfidence,
 		CreatedAt:          now,
 		UpdatedAt:          now,
 	}
@@ -566,7 +562,7 @@ func (h *trackerMappingHandler) identifyWithAgent(
 		"agent identified tracker pattern",
 		log.String("pattern", tp.Pattern),
 		log.String("third_party", identification.ThirdPartyName),
-		log.Float64("confidence", identification.Confidence),
+		log.Float64("third_party_confidence", identification.ThirdPartyConfidence),
 	)
 
 	return &catalogMatch{