feat(ui): rebuild all tools pages on Carbon Design System web components

- @carbon/web-components v2.50.0 via the IBM CDN (version-pinned);
  @carbon/styles CSS + IBM Plex Sans for tokens/typography
- landing: Carbon header + cds-tile tool cards
- fingerprint wizard: Carbon-styled form controls, cds-progress-bar scan
  progress, cds-tag badges, cds-inline-notification replacing swal
- cropper: cds-toast replacing toastr, cds-checkbox review reasons,
  cds-tag process badge; vue-croppa pad kept in the Carbon layout
- Bootstrap 4, swal, toastr and jQuery removed from all pages
- behavior frozen: same flows, endpoints, validation and copy

openspec/changes/archive/2026-10-01-carbon-ui-redesign/proposal.md

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+# Proposal: carbon-ui-redesign
+
+## Why
+
+The tools pages are styled with ad-hoc Bootstrap 4 overrides and ad-hoc dialogs
+(swal/toastr). Adopting the Carbon Design System gives the two tools a single
+professional design language (IBM Plex typography, Carbon components, Carbon
+tokens) consistent with the wider YOUreka ecosystem.
+
+## What Changes
+
+- **BREAKING (visual only)**: All three surfaces — landing, `/fingerprint`
+  wizard, `/cropper` — are rebuilt on Carbon Design System web components
+  (`@carbon/web-components` v2.50.0 via the IBM CDN, version-pinned) with IBM
+  Plex Sans typography and Carbon tokens for layout/colors.
+- Bootstrap 4, swal, toastr and jQuery are removed from the pages; errors and
+  confirmations surface as Carbon inline notifications and toasts.
+- Form fields use Carbon-styled native controls (text input, select, checkbox,
+  textarea) so Vue state bindings are unchanged; buttons, tags, notifications,
+  toasts, progress bar and tiles are Carbon web components.
+- **Behavior is frozen**: flows, endpoints, validation and copy stay exactly as
+  they are. The vue-croppa crop pad is kept (no Carbon equivalent), framed in a
+  Carbon tile/panel.
+
+## Capabilities
+
+### New Capabilities
+
+(none)
+
+### Modified Capabilities
+
+- `tools-app`: adds a requirement that the tools UI is built on Carbon Design
+  System web components with Carbon notifications.
+
+## Impact
+
+- Pages and `style.css` rewritten; `app.js` files adapted (notification/toast
+  models replace swal/toastr calls; `Vue.config.ignoredElements` for cds-*).
+- No server-side changes; no new npm dependencies; component JS + Plex font +
+  Carbon CSS delivered via CDN (IBM CDN for components, jsdelivr for
+  @carbon/styles, Google Fonts for Plex).