fix: inconsistency in /save and /load behavior with regard to file extensions (#289)

Author: Konippi

crates/chat-cli/src/cli/chat/cli/persist.rs

@@ -76,7 +76,23 @@ impl PersistSubcommand {
                 )?;
             },
             Self::Load { path } => {
-                let contents = tri!(os.fs.read_to_string(&path).await, "import from", &path);
+                // Try the original path first
+                let original_result = ctx.fs.read_to_string(&path).await;
+
+                // If the original path fails and doesn't end with .json, try with .json appended
+                let contents = if original_result.is_err() && !path.ends_with(".json") {
+                    let json_path = format!("{}.json", path);
+                    match ctx.fs.read_to_string(&json_path).await {
+                        Ok(content) => content,
+                        Err(_) => {
+                            // If both paths fail, return the original error for better user experience
+                            tri!(original_result, "import from", &path)
+                        },
+                    }
+                } else {
+                    tri!(original_result, "import from", &path)
+                };
+
                 let mut new_state: ConversationState = tri!(serde_json::from_str(&contents), "import from", &path);
                 new_state.reload_serialized_state(os).await;
                 session.conversation = new_state;