WIP: Modernize Sample Apps

[kirchoni]

Modernize Sample Apps → Kendo Meridian

Front-end modernization of KendoReact sample apps to the Meridian theme, driven by the
Design System Abstraction plugin (kendo-design). Part of the FE Design System
Abstraction effort — see FE-1257.

Status: WIP / cost-sampling. We modernized 2 apps first to measure per-app cost
before rolling the pipeline across the rest of the sample-app catalog.

Before / After

Apps modernized in this PR

App	Stack	Commit
AI Usage Monitoring Dashboard	React + Vite	57438141 Modernize AI usage dashboard
Coffee Warehouse	Next.js	62f6a647 Modernize Coffee Warehouse app

Each app also gains a DESIGN.md capturing its design guidance (adapted from Meridian's
default where the app needed it).

Process

• Agent: a refactor/modernization agent running a fixed modernization checklist prompt.
• Model: GPT-5.4.
• Plugin: kendo-design loaded for the session — bundles the kendo-design and
  kendo-themes skills, used as the source of truth for variable names, tokens, and theme
  customization conventions (no guessing from memory).
• Cost: ~$4 per sample app.

What the modernization covers

1. Theme → Meridian — replace the previously installed @progress/kendo-theme-* with
   @progress/kendo-theme-meridian (latest), updating every import/entry point.
2. Preserve app customizations — re-apply the app's own overrides (font, primary/base/
   status colors, radius, spacing, dark mode) on top of Meridian using Meridian's base tokens.
3. Icons → SVG (v5) — bump @progress/kendo-svg-icons, migrate off font icons where
   applicable, and bump peer @progress/kendo-react-* packages as needed.
4. Drop k-* utility classes — replace utility classNames in JSX with semantic,
   component-scoped CSS/SCSS reading from Kendo custom properties (--kendo-*) instead of
   hardcoded px/hex.
5. Bind to design tokens — rebind hardcoded values to the matching Kendo token modules
   (colors, typography, spacing, radii, elevation, motion, iconography, translucency).
6. Translucency — enable Meridian's frosted-glass system via --kendo-translucency-base
   (subtle), verifying legibility on elevated surfaces.

Verification

Per app: clean install, zero build/TypeScript/lint errors, and a manual click-through of the
main views with no runtime/console errors.

Not in this PR

• The remaining sample apps (rollout pending, gated on the cost sampling above).
• Design-level guidelines beyond Meridian's DESIGN.md — a separate UX effort
  (UX-577 /
  UX-568) will supply design specs,
  after which we'll re-run the same pipeline to apply them.