feat: show updated time in asset list

[luo1324574369]

Summary

• add an Updated column to the asset list on the homepage
• format the displayed timestamp on the client without changing backend APIs
• keep the implementation backward-compatible by falling back from updated to created to datetime
• shorten the column label to a compact table-friendly wording across locales

Why

The asset list previously showed type, amount, and currency, but it did not tell users when a row was last changed. That made it harder to answer basic questions such as:

• which asset entry was updated most recently
• whether a displayed amount is current or stale
• whether a recent manual edit has already taken effect

This change solves that with a low-risk frontend-only update. The backend already returns the necessary time fields, so adding the column in the UI avoids API churn and keeps the scope minimal.

Implementation Notes

• the new column is rendered in client/src/components/ChartWidget/TableWidget.svelte
• timestamp priority is:
  1. updated
  2. created
  3. datetime
• no server routes, controllers, or models were changed
• locale strings were added/updated for Chinese, Traditional Chinese, English, Japanese, and French
• the asset typing was extended so the frontend can consume created / updated safely

Verification

• cd client && npm run build

Build completed successfully. Existing repo warnings from Svelte/Tailwind remain, but this change does not introduce a new build failure.