added remove all item from queue

src/server/models/download.py

@@ -27,9 +27,9 @@ class DownloadStatus(str, Enum):
 class DownloadPriority(str, Enum):
     """Priority level for download queue items."""
 
-    LOW = "low"
-    NORMAL = "normal"
-    HIGH = "high"
+    LOW = "LOW"
+    NORMAL = "NORMAL"
+    HIGH = "HIGH"
 
 
 class EpisodeIdentifier(BaseModel):
@@ -175,9 +175,9 @@ class DownloadRequest(BaseModel):
     @field_validator('priority', mode='before')
     @classmethod
     def normalize_priority(cls, v):
-        """Normalize priority to lowercase for case-insensitive matching."""
+        """Normalize priority to uppercase for case-insensitive matching."""
         if isinstance(v, str):
-            return v.lower()
+            return v.upper()
         return v