fix:codeql scan Security issue

Author: msslulu

app/src/main/java/com/tinyengine/it/task/DatabaseCleanupService.java

@@ -12,7 +12,6 @@
 
 import jakarta.annotation.PostConstruct;
 
-import lombok.NoArgsConstructor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -42,6 +41,9 @@ public class DatabaseCleanupService {
     private static final DateTimeFormatter FORMATTER =
             DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
     private static final int EXEC_ID_LENGTH = 8;
+    private static final int HEX_NIBBLE_SHIFT = 4;
+    private static final int HEX_NIBBLE_MASK = 0x0F;
+    private static final int HEX_RADIX = 16;
 
     private final boolean cleanupEnabled;
     private final boolean useTruncate;
@@ -170,8 +172,10 @@ private static String createExecutionId() {
         random.nextBytes(randomBytes);
         final StringBuilder identifier = new StringBuilder(randomBytes.length * 2);
         for (final byte randomByte : randomBytes) {
-            identifier.append(Character.forDigit((randomByte >>> 4) & 0x0F, 16));
-            identifier.append(Character.forDigit(randomByte & 0x0F, 16));
+            identifier.append(
+                    Character.forDigit(
+                            (randomByte >>> HEX_NIBBLE_SHIFT) & HEX_NIBBLE_MASK, HEX_RADIX));
+            identifier.append(Character.forDigit(randomByte & HEX_NIBBLE_MASK, HEX_RADIX));
         }
         return identifier.substring(0, EXEC_ID_LENGTH);
     }

base/src/main/java/com/tinyengine/it/rag/config/ChromaStoreFactory.java

@@ -8,7 +8,8 @@
 
 /** Creates Chroma embedding stores from validated connection settings. */
 public final class ChromaStoreFactory {
-    private ChromaStoreFactory() {}
+    private ChromaStoreFactory() {
+    }
 
     public static EmbeddingStore<TextSegment> create(
             final String baseUrl, final String collectionName, final Duration timeout) {

base/src/main/java/com/tinyengine/it/rag/config/VectorStoreConfig.java

@@ -105,7 +105,7 @@ public EmbeddingStore<TextSegment> embeddingStore() {
                 logWarn("ChromaDB initialization failed, using fallback embedding store", exception);
             }
         } else {
-                logWarn("ChromaDB connection test failed, using fallback embedding store");
+            logWarn("ChromaDB connection test failed, using fallback embedding store");
         }
         return embeddingStore;
     }

base/src/test/java/com/tinyengine/it/common/utils/SM4UtilsTest.java

@@ -13,8 +13,7 @@ class SM4UtilsTest {
     private static final int SHORT_KEY_LEN = 8;
     private final int invalidKeyLength;
 
-    /** Initializes the invalid key length used by validation tests. */
-    public SM4UtilsTest() {
+    /* default */ SM4UtilsTest() {
         invalidKeyLength = SHORT_KEY_LEN;
     }