fix(cortex-cli): check actual write permission for current user in debug file

cortex-cli/src/debug_cmd.rs

@@ -340,6 +340,10 @@ async fn run_file(args: FileArgs) -> Result<()> {
                     None
                 };
 
+                // Check if the current user can actually write to the file
+                // This is more accurate than just checking permission bits
+                let readonly = !is_writable_by_current_user(&path);
+
                 (
                     Some(FileMetadata {
                         size: meta.len(),
@@ -349,7 +353,7 @@ async fn run_file(args: FileArgs) -> Result<()> {
                         symlink_target,
                         modified,
                         created,
-                        readonly: meta.permissions().readonly(),
+                        readonly,
                     }),
                     None,
                 )
@@ -506,6 +510,16 @@ fn guess_mime_type(ext: &str) -> String {
     .to_string()
 }
 
+/// Check if the current user can write to the file.
+///
+/// This function attempts to open the file for writing to determine
+/// if the current user has write access. This is more accurate than
+/// checking permission bits, as it accounts for ownership, group
+/// membership, and ACLs.
+fn is_writable_by_current_user(path: &std::path::Path) -> bool {
+    std::fs::OpenOptions::new().write(true).open(path).is_ok()
+}
+
 /// Detect encoding and binary status.
 fn detect_encoding_and_binary(path: &PathBuf) -> (Option<String>, Option<bool>) {
     // Read first 8KB to check for binary content