fix: Implement std::fmt::Display for Permission to resolve compilation errors

backend/src/models/permission.rs

@@ -1,9 +1,8 @@
 use serde::{Deserialize, Serialize};
-use strum::{Display, EnumString};
+use std::fmt;
 
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Display, EnumString)]
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
 #[serde(rename_all = "lowercase")]
-#[strum(serialize_all = "lowercase")]
 pub enum Permission {
     Read,
     Write,
@@ -12,6 +11,18 @@ pub enum Permission {
     Admin,
 }
 
+impl fmt::Display for Permission {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Read => write!(f, "read"),
+            Self::Write => write!(f, "write"),
+            Self::Delete => write!(f, "delete"),
+            Self::Share => write!(f, "share"),
+            Self::Admin => write!(f, "admin"),
+        }
+    }
+}
+
 impl Permission {
     pub fn can_read(&self) -> bool {
         matches!(self, Self::Read | Self::Admin)