fix(db): 放宽 release_package 唯一约束，支持同平台多文件（dmg + app.tar.gz）

- 唯一约束从 (release_id, platform, architecture) 改为包含 filename
- 新增 Alembic 迁移 7d855b38fe83

python-api/alembic/versions/7d855b38fe83_add_filename_to_release_package_unique_.py

@@ -0,0 +1,41 @@
+"""add filename to release_package unique constraint
+
+Revision ID: 7d855b38fe83
+Revises: 8d901bc90e67
+Create Date: 2026-05-26 22:55:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision: str = '7d855b38fe83'
+down_revision: Union[str, Sequence[str], None] = '8d901bc90e67'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # 删除旧约束（release_id + platform + architecture）
+    op.drop_constraint('uix_app_pkg_platform_arch', 'mjk_app_release_packages', type_='unique')
+    # 创建新约束（release_id + platform + architecture + filename）
+    op.create_unique_constraint(
+        'uix_app_pkg_platform_arch_filename',
+        'mjk_app_release_packages',
+        ['release_id', 'platform', 'architecture', 'filename']
+    )
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # 删除新约束
+    op.drop_constraint('uix_app_pkg_platform_arch_filename', 'mjk_app_release_packages', type_='unique')
+    # 恢复旧约束
+    op.create_unique_constraint(
+        'uix_app_pkg_platform_arch',
+        'mjk_app_release_packages',
+        ['release_id', 'platform', 'architecture']
+    )

python-api/app/models/update.py

@@ -60,5 +60,5 @@ class ReleasePackage(Base):
     release: Mapped["AppRelease"] = relationship("AppRelease", back_populates="packages")
 
     __table_args__ = (
-        UniqueConstraint("release_id", "platform", "architecture", name="uix_app_pkg_platform_arch"),
+        UniqueConstraint("release_id", "platform", "architecture", "filename", name="uix_app_pkg_platform_arch_filename"),
     )