Fix missing bounds checks, unsafe JSON.parse, and cleanup issues

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/stores/files.ts

@@ -174,8 +174,10 @@ export const useFilesStore = defineStore("filesStore", {
           // msg: 'not in UTF-8' | 'insufficient columns' | 'the csv file is empty' | 'the filename does not ends with .csv'
           // type: 'encoding' | 'insufficient_columns' | 'empty' | 'name_suffix'
           const detail = error.response.data.detail;
-
-          uploadFailedFirst(detail[0].type, detail[0].msg, detail[0].loc[2]);
+          if (Array.isArray(detail) && detail.length > 0) {
+            const loc = detail[0].loc;
+            uploadFailedFirst(detail[0].type, detail[0].msg, Array.isArray(loc) && loc.length > 2 ? loc[2] : undefined);
+          }
         } else {
           Swal.close(); // Close the loading progress bar
           apiError(error, "Failed to upload the files.");