fix(ebooks): account canceled and vanished claims accurately

A claim whose enrichment surfaced context.Canceled while the sweep was
still live was released uncounted, leaving it immediately reclaimable and
invisible to the no-progress circuit breaker. Let it flow through the
failure path as a transient error so it backs off and is counted; genuine
sweep shutdown still releases via the existing ctx check.

Claims discarded because the item vanished are terminal, not retried, so
report them in a new discarded counter instead of inflating deferred, and
surface the count in task progress output.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/ebooks/enrichment.go

@@ -116,6 +116,7 @@ type EnrichmentRunResult struct {
 	NoMatch   int  `json:"no_match"`
 	Failed    int  `json:"failed"`
 	Deferred  int  `json:"deferred"`
+	Discarded int  `json:"discarded"`
 	Remaining int  `json:"remaining"`
 	HasMore   bool `json:"-"`
 }
@@ -282,6 +283,7 @@ func (e *Enricher) RunLimited(ctx context.Context, scope EnrichmentScope, maxCla
 		"no_match", result.NoMatch,
 		"failed", result.Failed,
 		"deferred", result.Deferred,
+		"discarded", result.Discarded,
 		"has_more", result.HasMore,
 	)
 	return result, runErr
@@ -325,7 +327,7 @@ func (e *Enricher) runQueueBatch(
 			if err := e.discardJob(queue, job); err != nil && !errors.Is(err, ErrEnrichmentLeaseLost) {
 				transitionErrs = append(transitionErrs, fmt.Errorf("%s: %w", job.ContentID, err))
 			} else if err == nil {
-				result.Deferred++
+				result.Discarded++
 			}
 		}
 	}
@@ -405,10 +407,6 @@ func (e *Enricher) runQueueBatch(
 					}
 					continue
 				}
-				if errors.Is(enrichErr, context.Canceled) {
-					recordTransitionError(item.ContentID, e.releaseJob(queue, job))
-					continue
-				}
 				if enrichErr != nil {
 					errorClass, retryAfter := classifyEnrichmentError(enrichErr)
 					transitionErr := e.failJob(

internal/ebooks/enrichment_test.go

@@ -402,7 +402,8 @@ func TestEnricherRunDiscardsClaimedRowsThatAreNoLongerEligible(t *testing.T) {
 		},
 	}
 
-	if _, err := e.Run(context.Background(), EnrichmentScopeIncremental); err != nil {
+	result, err := e.Run(context.Background(), EnrichmentScopeIncremental)
+	if err != nil {
 		t.Fatalf("Run() error = %v", err)
 	}
 	if got := strings.Join(queue.discarded, ","); got != "became-manga" {
@@ -414,6 +415,43 @@ func TestEnricherRunDiscardsClaimedRowsThatAreNoLongerEligible(t *testing.T) {
 	if len(queue.released) != 0 {
 		t.Fatalf("ineligible rows were released back into immediate churn: %v", queue.released)
 	}
+	if result.Discarded != 1 {
+		t.Fatalf("Discarded = %d, want 1", result.Discarded)
+	}
+	if result.Deferred != 1 {
+		t.Fatalf("Deferred = %d, want 1 (the skipped completion only); a discarded row is terminal, not deferred for retry", result.Deferred)
+	}
+}
+
+func TestEnricherRunCountsUpstreamCancellationAsTransientFailure(t *testing.T) {
+	queue := &fakeEnrichmentQueue{
+		jobs: []EnrichmentJob{{ContentID: "cancel-happy", Token: "cancel-token", Attempts: 1}},
+	}
+	e := &Enricher{
+		queue:     queue,
+		batchSize: 1,
+		workers:   1,
+		loadClaimedItemsFn: func(context.Context, []EnrichmentJob) ([]enrichmentItemRow, error) {
+			return []enrichmentItemRow{{ContentID: "cancel-happy"}}, nil
+		},
+		enrichClaimedItemFn: func(context.Context, enrichmentItemRow) (EnrichmentOutcome, error) {
+			return "", context.Canceled
+		},
+	}
+
+	result, err := e.Run(context.Background(), EnrichmentScopeIncremental)
+	if err != nil {
+		t.Fatalf("Run() error = %v", err)
+	}
+	if got := queue.failed["cancel-happy"]; got != EnrichmentErrorTransient {
+		t.Fatalf("failure class = %q, want transient", got)
+	}
+	if result.Failed != 1 {
+		t.Fatalf("Failed = %d, want 1; an uncounted claim blinds the no-progress circuit breaker", result.Failed)
+	}
+	if len(queue.released) != 0 {
+		t.Fatalf("provider-canceled work was released into immediate reclaim churn: %v", queue.released)
+	}
 }
 
 func TestEnricherRunBoundsEachItemBelowTheLease(t *testing.T) {

internal/taskmanager/tasks/sync_ebook_metadata.go

@@ -231,6 +231,7 @@ func addEbookEnrichmentResult(total *ebooks.EnrichmentRunResult, batch ebooks.En
 	total.NoMatch += batch.NoMatch
 	total.Failed += batch.Failed
 	total.Deferred += batch.Deferred
+	total.Discarded += batch.Discarded
 }
 
 func reportEbookEnrichmentProgress(
@@ -246,12 +247,13 @@ func reportEbookEnrichmentProgress(
 		percent = 100
 	}
 	progress.Report(percent, fmt.Sprintf(
-		"Claimed %d, enriched %d, no match %d, failed %d, deferred %d, remaining %d",
+		"Claimed %d, enriched %d, no match %d, failed %d, deferred %d, discarded %d, remaining %d",
 		result.Claimed,
 		result.Enriched,
 		result.NoMatch,
 		result.Failed,
 		result.Deferred,
+		result.Discarded,
 		result.Remaining,
 	))
 }
@@ -287,13 +289,14 @@ func reportEbookEnrichmentPause(
 		percent = 99
 	}
 	progress.Report(percent, fmt.Sprintf(
-		"%s Claimed %d, enriched %d, no match %d, failed %d, deferred %d, remaining %d",
+		"%s Claimed %d, enriched %d, no match %d, failed %d, deferred %d, discarded %d, remaining %d",
 		message,
 		result.Claimed,
 		result.Enriched,
 		result.NoMatch,
 		result.Failed,
 		result.Deferred,
+		result.Discarded,
 		result.Remaining,
 	))
 }