feat: implement production cas v1

crates/bat-cas-engine/src/error.rs

@@ -22,6 +22,14 @@ pub enum CasError {
     #[error("Object not found: {0}")]
     ObjectNotFound(String),
 
+    /// Hash 格式无效
+    #[error("Invalid hash: {0}")]
+    InvalidHash(String),
+
+    /// 引用计数下溢
+    #[error("Reference count is already zero: {0}")]
+    ReferenceUnderflow(String),
+
     /// 数据库错误
     #[error("Database error: {0}")]
     Database(String),
@@ -33,3 +41,9 @@ pub enum CasError {
 
 /// CAS Engine Result 类型
 pub type Result<T> = std::result::Result<T, CasError>;
+
+impl From<sqlx::Error> for CasError {
+    fn from(error: sqlx::Error) -> Self {
+        Self::Database(error.to_string())
+    }
+}