Fix updater: strip v-prefix from version in latest.json, and delete
old package before re-uploading to avoid 409 conflicts.
Add frontend log capture (console intercept) with a log viewer card
in the settings page (filterable, copyable, clearable).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add export (JSON/CSV) and import (full replace) to the Settings page.
Export supports 3 modes (transactions+categories, transactions only,
categories only) with optional password encryption using Argon2id key
derivation. Import detects encrypted .sref files, prompts for password,
and shows a destructive confirmation modal before replacing data.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
