fix(openai): artifact receipt의 중복 history gate를 제거한다

apps/edge/internal/openai/artifact_pair.go

@@ -645,7 +645,7 @@ func (s *artifactFrontierStore) consume(
 		return logicalRequestSnapshot{}, artifactDisposition{}, true, fmt.Errorf("artifact receipt rejected: result contains an explicit error signal")
 	}
 
-	snap, err := coordinator.consumeContinuationByLineage(ownerEdgeID, principalRef, lineage)
+	snap, err := coordinator.consumeArtifactContinuationByLineage(record.requestID, ownerEdgeID, principalRef, lineage)
 	if err != nil {
 		return logicalRequestSnapshot{}, artifactDisposition{}, true, err
 	}
@@ -712,7 +712,11 @@ func (s *artifactFrontierStore) matchRecordLocked(
 		if record.protocol != protocol {
 			return nil, true, fmt.Errorf("%w: protocol changed", errLogicalRequestLineage)
 		}
-		if record.lineage != lineage.Prefix {
+		// Artifact receipts are already bound to the owner, principal, protocol,
+		// toolset, exact issued-call hash, call ids, and result matcher. The light
+		// flow also retains the immutable task independently, so caller SDK history
+		// reserialization is not an additional receipt boundary.
+		if record.lineage.Endpoint != lineage.Prefix.Endpoint || record.lineage.ToolsetDigest != lineage.Prefix.ToolsetDigest {
 			return nil, true, describeArtifactPrefixMismatch(record.lineage, lineage.Prefix)
 		}
 		return record, true, nil

apps/edge/internal/openai/artifact_pair_test.go

@@ -234,6 +234,28 @@ func TestArtifactPairFrontierMatrix(t *testing.T) {
 				}
 				fixture.assertPhase(artifactPhaseLocalEligible)
 			})
+
+			t.Run("exact receipt tolerates caller history reserialization", func(t *testing.T) {
+				fixture := newArtifactPairFixture(t, endpoint, true)
+				ids := fixture.issuePair()
+				body := fixture.continuationBody([]artifactTestResult{
+					{id: ids[0], body: `{"written":true}`},
+					{id: ids[1], body: `{"written":true}`},
+				}, nil)
+				var envelope map[string]any
+				if err := json.Unmarshal(body, &envelope); err != nil {
+					t.Fatal(err)
+				}
+				messages := envelope["messages"].([]any)
+				messages[0].(map[string]any)["content"] = []any{map[string]any{
+					"type": "text", "text": "task", "cache_control": map[string]any{"type": "ephemeral"},
+				}}
+				body, _ = json.Marshal(envelope)
+				if _, _, err := fixture.continueRaw(body); err != nil {
+					t.Fatalf("exact receipt rejected reserialized history: %v", err)
+				}
+				fixture.assertPhase(artifactPhaseLocalEligible)
+			})
 		})
 	}
 }

apps/edge/internal/openai/request_coordinator.go

@@ -427,6 +427,41 @@ func (c *logicalRequestCoordinator) consumeContinuationByLineage(ownerEdgeID, pr
 	return target.snapshot(), nil
 }
 
+func (c *logicalRequestCoordinator) consumeArtifactContinuationByLineage(
+	requestID, ownerEdgeID, principalRef string,
+	lineage logicalRequestContinuationLineage,
+) (logicalRequestSnapshot, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	record, ok := c.requests[requestID]
+	if !ok || record.state != logicalRequestStateWaiting {
+		return logicalRequestSnapshot{}, errLogicalRequestNotFound
+	}
+	if record.ownerEdgeID != ownerEdgeID {
+		return logicalRequestSnapshot{}, errLogicalRequestOwnerMismatch
+	}
+	if record.principalRef != principalRef {
+		return logicalRequestSnapshot{}, errLogicalRequestPrincipal
+	}
+	if record.lineage.Endpoint != lineage.Prefix.Endpoint || record.lineage.ToolsetDigest != lineage.Prefix.ToolsetDigest {
+		return logicalRequestSnapshot{}, errLogicalRequestLineage
+	}
+	if record.expected == nil {
+		return logicalRequestSnapshot{}, errLogicalRequestNoFrontier
+	}
+	if record.expectedIssuedCallHash != lineage.IssuedCallHash || !sameLogicalRequestResultIDs(record.expected, lineage.ResultIDs) {
+		return logicalRequestSnapshot{}, errLogicalRequestFrontier
+	}
+
+	record.expected = nil
+	record.expectedIssuedCallHash = ""
+	record.lineage = lineage.Committed
+	record.activeStageID = ""
+	record.state = logicalRequestStateResumed
+	record.updatedAt = c.now()
+	return record.snapshot(), nil
+}
+
 func (c *logicalRequestCoordinator) snapshot(requestID string) (logicalRequestSnapshot, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()