fix(frontend): upcoming-purchase details dialog focuses the destructive Cancel Purchase button #1653

Summary

The upcoming-purchase details dialog puts initial focus on the destructive "Cancel Purchase" button.

Current behaviour

In the details dialog (frontend/src/dashboard.ts, ~line 720-745) "Cancel Purchase" is the first button. It opens a confirm, so one keypress cannot cancel anything, but focus should land on a safe control.

Steps to reproduce

1. Open Home, then "View Details" on an upcoming purchase you can cancel.
2. Observe the focused element.

Expected behaviour

Initial focus lands on "Close" (or the dialog heading).

Proposed fix

Focus #close-purchase-details-btn after opening, or place it first in DOM order, in frontend/src/dashboard.ts.

References

Discovered while reviewing #1598.

Severity

low