Guard popup import flow against invalid backups and read errors

Importing data in the popup assumed file reads, JSON parsing, and
storage writes would always succeed, leaving failures unhandled and
giving users no feedback.

Catch errors across the import flow and validate that parsed backup data
is a plain object before writing it to storage, so invalid files fail
clearly without changing the successful restore path.

Author: PeterDaveHello

src/popup/sections/GeneralPart.jsx

@@ -568,13 +568,36 @@ export function GeneralPart({ config, updateConfig, setTabIndex }) {
               input.click()
             })
             if (!file) return
-            const data = await new Promise((resolve) => {
-              const reader = new FileReader()
-              reader.onload = (e) => resolve(JSON.parse(e.target.result))
-              reader.readAsText(file)
-            })
-            await importDataIntoStorage(Browser.storage.local, data)
-            window.location.reload()
+            try {
+              const fileContent =
+                typeof file.text === 'function'
+                  ? await file.text()
+                  : await new Promise((resolve, reject) => {
+                      const reader = new FileReader()
+                      reader.onload = () => resolve(reader.result)
+                      reader.onerror = () => reject(reader.error)
+                      reader.readAsText(file)
+                    })
+              const parsedData = JSON.parse(fileContent)
+              const isPlainObject =
+                parsedData !== null && typeof parsedData === 'object' && !Array.isArray(parsedData)
+
+              if (!isPlainObject) {
+                throw new Error('Invalid backup file')
+              }
+
+              await importDataIntoStorage(Browser.storage.local, parsedData)
+              window.location.reload()
+            } catch (error) {
+              console.error('[popup] Failed to import data', error)
+              const rawMessage =
+                error instanceof SyntaxError
+                  ? 'Invalid backup file'
+                  : error instanceof Error
+                  ? error.message
+                  : String(error ?? '')
+              window.alert(rawMessage ? `${t('Error')}: ${rawMessage}` : t('Error'))
+            }
           }}
         >
           {t('Import All Data')}