refactor(#779): 消除重复枚举定义，统一到classification模块

- AssetLibraryKind: 从entities.py+classification.py双份定义，统一到classification.py
- IngestJobStatus: 同上
- ClassificationStatus/ClassificationJobStatus: 合并为ClassificationJobStatus，保留_missing_兼容方法，ClassificationStatus作为别名
- entities.py改为re-export兼容层，107处import不受影响
- 补齐classification.py中AssetLibraryKind缺失的IMAGE值
- 净减8行

packages/domain/classification.py

@@ -19,6 +19,7 @@ from uuid import uuid4
 class AssetLibraryKind(StrEnum):
     VIDEO = "video"
     VOICE = "voice"
+    IMAGE = "image"
 
 
 class IngestJobStatus(StrEnum):
@@ -34,6 +35,27 @@ class ClassificationJobStatus(StrEnum):
     COMPLETED = "completed"
     FAILED = "failed"
 
+    @classmethod
+    def _missing_(cls, value: object) -> "ClassificationJobStatus":
+        """兼容历史数据，避免枚举转换失败导致500。
+
+        - done → COMPLETED（早期版本用 done 表示完成）
+        - 其他未知值 → PENDING（兜底，不阻塞业务）
+        """
+        if isinstance(value, str):
+            normalized = value.strip().lower()
+            if normalized in ("done", "success", "finished", "complete"):
+                return cls.COMPLETED
+            if normalized in ("fail", "error", "err"):
+                return cls.FAILED
+            if normalized in ("process", "processing", "running", "run"):
+                return cls.PROCESSING
+        return cls.PENDING
+
+
+# 向后兼容别名
+ClassificationStatus = ClassificationJobStatus
+
 
 class AssetClassification(StrEnum):
     """Asset classification categories."""

packages/domain/entities.py

@@ -16,18 +16,12 @@ else:
 from typing import Any
 from uuid import uuid4
 
-
-class AssetLibraryKind(StrEnum):
-    VIDEO = "video"
-    VOICE = "voice"
-    IMAGE = "image"
-
-
-class IngestJobStatus(StrEnum):
-    PENDING = "pending"
-    PROCESSING = "processing"
-    COMPLETED = "completed"
-    FAILED = "failed"
+# 枚举统一从 classification 模块导入，消除重复定义
+from packages.domain.classification import (
+    AssetLibraryKind,
+    ClassificationStatus,
+    IngestJobStatus,
+)
 
 
 @dataclass(slots=True)
@@ -160,30 +154,6 @@ class AssetStatus(StrEnum):
         return cls.READY
 
 
-class ClassificationStatus(StrEnum):
-    PENDING = "pending"
-    PROCESSING = "processing"
-    COMPLETED = "completed"
-    FAILED = "failed"
-
-    @classmethod
-    def _missing_(cls, value: object) -> "ClassificationStatus":
-        """兼容历史数据，避免枚举转换失败导致500。
-
-        - done → COMPLETED（早期版本用 done 表示完成）
-        - 其他未知值 → PENDING（兜底，不阻塞业务）
-        """
-        if isinstance(value, str):
-            normalized = value.strip().lower()
-            if normalized in ("done", "success", "finished", "complete"):
-                return cls.COMPLETED
-            if normalized in ("fail", "error", "err"):
-                return cls.FAILED
-            if normalized in ("process", "processing", "running", "run"):
-                return cls.PROCESSING
-        return cls.PENDING
-
-
 @dataclass(slots=True)
 class Asset:
     id: str