Store SHA256 checksums with artifacts and add multiple hash support

backend/app/models.py

@@ -74,7 +74,9 @@ class Artifact(Base):
     content_type = Column(String(255))
     original_name = Column(String(1024))
     checksum_md5 = Column(String(32))  # MD5 hash for additional verification
-    metadata = Column(JSON, default=dict)  # Format-specific metadata
+    checksum_sha1 = Column(String(40))  # SHA1 hash for compatibility
+    s3_etag = Column(String(64))  # S3 ETag for verification
+    artifact_metadata = Column("metadata", JSON, default=dict)  # Format-specific metadata (column name is 'metadata')
     created_at = Column(DateTime(timezone=True), default=datetime.utcnow)
     created_by = Column(String(255), nullable=False)
     ref_count = Column(Integer, default=1)
@@ -83,6 +85,21 @@ class Artifact(Base):
     tags = relationship("Tag", back_populates="artifact")
     uploads = relationship("Upload", back_populates="artifact")
 
+    @property
+    def sha256(self) -> str:
+        """Alias for id - the SHA256 hash of the artifact content"""
+        return self.id
+
+    @property
+    def format_metadata(self):
+        """Alias for artifact_metadata - backward compatibility"""
+        return self.artifact_metadata
+
+    @format_metadata.setter
+    def format_metadata(self, value):
+        """Alias setter for artifact_metadata - backward compatibility"""
+        self.artifact_metadata = value
+
     __table_args__ = (
         Index("idx_artifacts_created_at", "created_at"),
         Index("idx_artifacts_created_by", "created_by"),