Improve error handling and logging for map generation process

src-tauri/src/main.rs

@@ -457,9 +457,15 @@ async fn generate_map(
                 cmd.arg(arg);
             }
 
-            let mut child = cmd
+            let mut child = match cmd.spawn() {
-                .spawn()
+                Ok(child) => child,
-                .map_err(|e| format!("Failed to start generator: {e}"))?;
+                Err(e) => {
+                    write_log_line(&mut log_file, format!("result: spawn_failed: {e}"));
+                    return Err(format!(
+                        "Failed to start generator. Log: {log_path_display}\n{e}"
+                    ));
+                }
+            };
             write_log_line(&mut log_file, format!("pid: {}", child.id()));
             write_log_line(&mut log_file, "");
             write_log_line(&mut log_file, "stdout:");
@@ -536,15 +542,22 @@ async fn generate_map(
                 ));
             }
 
-            let path_line =
+            let path_line = match last_path {
-                last_path.ok_or_else(|| "Generator did not return a path".to_string())?;
+                Some(path) => path,
+                None => {
+                    write_log_line(&mut log_file, "result: missing_output_path");
+                    return Err(format!(
+                        "Generator did not return a path. Log: {log_path_display}"
+                    ));
+                }
+            };
             let path = PathBuf::from(path_line.trim());
             let resolved = if path.is_absolute() {
                 path
             } else {
                 out_dir.join(path)
             };
-            write_log_line(&mut log_file, format!("result: success"));
+            write_log_line(&mut log_file, "result: success");
             write_log_line(
                 &mut log_file,
                 format!("output_path: {}", resolved.to_string_lossy()),