Frontend structure

The frontend is split by responsibility:

src/app - application shell/orchestration (global state composition, page-level flow, feature wiring).
src/features - domain features grouped by capability:
- mixer - channel cards, target assignment UI, mixer-specific constants/helpers.
- settings - settings-only form components.
- calibration - calibration overlay and calibration-specific UI.
- updates - app update panel UI.
src/components/ui - design-system primitives (shared UI building blocks).
src/hooks - reusable React hooks.
src/lib - pure domain logic, API adapters, utilities and tests.
src/types - ambient type declarations.

Rules for maintainability

Keep orchestration in src/app, keep feature UI in src/features/*/components.
Avoid adding feature-specific components back into src/app/App.tsx.
If a component needs feature constants/helpers, keep them in the same feature folder.
Keep src/lib framework-agnostic when possible.