feat: 审核通过移动文件到approved，拒绝删除pending文件

- StorageService 新增 delete()
- approve: 文件 pending → approved
- reject: 删除 pending 文件

par-core/src/main/java/com/par/core/storage/CachedStorageService.java

@@ -55,4 +55,10 @@ public class CachedStorageService implements StorageService {
         if (isQiniuMode()) return local.exists(path) || qiniu.exists(path);
         return local.exists(path);
     }
+
+    @Override
+    public void delete(String path) {
+        local.delete(path);
+        if (isQiniuMode()) qiniu.delete(path);
+    }
 }

par-core/src/main/java/com/par/core/storage/LocalStorageService.java

@@ -63,4 +63,13 @@ public class LocalStorageService implements StorageService {
     public boolean exists(String path) {
         return Files.exists(baseDir.resolve(path));
     }
+
+    @Override
+    public void delete(String path) {
+        try {
+            Files.deleteIfExists(baseDir.resolve(path));
+        } catch (IOException e) {
+            log.warn("删除文件失败 {}: {}", path, e.getMessage());
+        }
+    }
 }

par-core/src/main/java/com/par/core/storage/QiniuStorageService.java

@@ -93,6 +93,17 @@ public class QiniuStorageService implements StorageService {
         }
     }
 
+    @Override
+    public void delete(String path) {
+        ensureInit();
+        try {
+            bucketManager.delete(bucket, path);
+            log.debug("Qiniu 删除: {}", path);
+        } catch (QiniuException e) {
+            log.warn("Qiniu 删除失败 {}: {}", path, e.response != null ? e.response.error : e.getMessage());
+        }
+    }
+
     private static String env(String key) { return System.getenv(key); }
     private static String env(String key, String def) {
         String v = System.getenv(key);

par-core/src/main/java/com/par/core/storage/StorageService.java

@@ -15,4 +15,7 @@ public interface StorageService {
 
     /** 检查是否存在 */
     boolean exists(String path);
+
+    /** 删除文件 */
+    void delete(String path);
 }