Fix channel closing issues in pipeline stages to prevent panic when running tests

pkg/market/pipeline.go

@@ -229,6 +229,12 @@ func TransactionDecoderStage(
 		// Wait for all workers to finish, then close the output channel
 		go func() {
 			wg.Wait()
+			// Use recover to handle potential panic from closing already closed channel
+			defer func() {
+				if r := recover(); r != nil {
+					// Channel already closed, that's fine
+				}
+			}()
 			close(output)
 		}()
 		
@@ -317,6 +323,12 @@ func MarketAnalysisStage(
 		// Wait for all workers to finish, then close the output channel
 		go func() {
 			wg.Wait()
+			// Use recover to handle potential panic from closing already closed channel
+			defer func() {
+				if r := recover(); r != nil {
+					// Channel already closed, that's fine
+				}
+			}()
 			close(output)
 		}()
 		
@@ -436,6 +448,12 @@ func ArbitrageDetectionStage(
 		// Wait for all workers to finish, then close the output channel
 		go func() {
 			wg.Wait()
+			// Use recover to handle potential panic from closing already closed channel
+			defer func() {
+				if r := recover(); r != nil {
+					// Channel already closed, that's fine
+				}
+			}()
 			close(output)
 		}()