Improve music processing robustness and workflow UX

Unify safe file-move behavior and richer progress semantics across backend tasks, while upgrading traditional-to-simplified conversion and refining the frontend multi-step panels for clearer execution feedback.

backend/pom.xml

@@ -72,6 +72,13 @@
             <artifactId>pinyin4j</artifactId>
             <version>2.5.1</version>
         </dependency>
+
+        <!-- OpenCC Java 实现：繁简转换（词典驱动，减少手工维护成本） -->
+        <dependency>
+            <groupId>com.github.houbb</groupId>
+            <artifactId>opencc4j</artifactId>
+            <version>1.13.1</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -93,4 +100,3 @@
         </plugins>
     </build>
 </project>
-