# design-sync NOTES — tradein-mvp-frontend

Target: `tradein-mvp/frontend` (NOT the repo-root `frontend/`, which is the Site-Finder app). Project: gendesign-tradein.

## Build gotchas
- **No dist / no Storybook → synth-entry mode.** The package is a Next.js app, not a lib; `package.json` has no `main`/`module`/`exports`.
- **`--entry` must point at a NON-existent dist path** (`tradein-mvp/frontend/dist/index.js`). Two jobs:
  1. PKG_DIR resolution walks up `dirname(--entry)` to the real named `package.json` → PKG_DIR=`tradein-mvp/frontend` (without `--entry`, PKG_DIR defaults to `node_modules/<pkg>` which doesn't self-install → ENOENT crash).
  2. The path being absent makes `resolveDistEntry(soft)` return null → `synthEntry=true` → `deriveComponentsFromSrc` discovers components from `src/`. A path that EXISTS (e.g. package.json) suppresses synth mode → `[ZERO_MATCH]` tokens-only.
- **`cfg.*` path fields are PACKAGE-relative** (relative to PKG_DIR), not repo-relative. srcDir=`src`, cssEntry=`src/components/trade-in/trade-in.css`, tokensGlob=`src/app/globals.css`.
- `--node-modules tradein-mvp/frontend/node_modules` (react + @types/react live there).

## Styling
- Tokens in `src/app/globals.css` (`:root{--bg-app,--accent,…}`); component CSS in `src/components/trade-in/trade-in.css` (2277 lines). Manrope via remote Google Fonts `@import` (→ `[FONT_REMOTE]`, no action).

## Re-sync risks
- Synth scan over-includes non-component PascalCase exports (51 found vs ~37 files) — prune with `componentSrcMap: {Name: null}` as identified.
- Components are app-coupled (next/*, TanStack Query, data hooks); many need providers/mock props to render → expect floor cards / authored previews with composed props.

## Authoring (38 components, all authored-good)
- **Import contract:** preview imports `{X} from 'tradein-mvp-frontend'` (mapped to window.TradeInUI bundle) + data from `./_fixtures` (re-exports the repo's offline `app/ui-preview/estimate/fixture.ts`). Type imports erased.
- **Provider = seeded `PreviewProvider`** (`.design-sync/preview-provider.tsx`, wired via `cfg.extraEntries` + `cfg.provider`). Mirrors `app/ui-preview/estimate/page.tsx`'s seeded QueryClient: pre-fills `["auth","me"]` (fake admin user) + the estimate sub-queries (placement-history, house-analytics, sell-time-sensitivity, cian-price-changes=[], sales-vs-listings). This is what makes fetch-coupled cards (StreetDealsCard, HouseAnalyticsSection, PlacementHistoryCard) and auth-gated ones (RouteGuard, UserMenu) render offline.
  - **CRITICAL:** an extraEntries module must NOT import anything that reads `process.env` at module top-level (e.g. `@/lib/useMe` → `@/lib/api`) — extraEntries evaluate BEFORE the synth-entry `.pkg-shim.mjs`, so `process` is undefined and the whole IIFE aborts (38/38 vanish from the global). The provider hardcodes `ME_QUERY_KEY = ["auth","me"]` instead of importing useMe.
  - extraEntries path is PACKAGE-relative: `../../.design-sync/preview-provider.tsx`. Its `@/` aliases don't resolve from outside the tsconfig root → use relative `../tradein-mvp/frontend/src/...` for repo imports inside it.
- **Chart cards gate on analog count ≥8** (DistributionCard, ExposureCard): the shared fixture has 3 analogs → "not enough data" fallback. Those two previews extend `analogs` to 10 realistic ЕКБ lots INLINE in their own preview file (spread FIXTURE_ESTIMATE, override analogs+n_analogs) — never edit `_fixtures.ts`.
- **Admin/scraper panels** (DataQualitySection, ProviderProxySection, RunsTable, PacingSection, SystemHealthSection) fetch their own data with no repo fixture → they render their real styled LOADING/header state. Graded good as honest states; richer data would need admin fixtures that don't exist in the repo.
- **MapCard / MapPicker**: Leaflet from unpkg loads in the capture env; OSM raster tiles sometimes don't paint within the screenshot window (external tile fetch) — markers/popup/controls still render. Both graded good. MapPicker is a `createPortal` full-viewport overlay — rendered contained in capture; if a future capture viewport change makes it escape, add `cfg.overrides.MapPicker.cardMode`/`viewport`.

## Re-sync risks
- The `process` shim env defaults live in `.design-sync/overrides/source-kit.mjs` (synth entry). If the app reads NEW `process.env.NEXT_PUBLIC_*` vars, add them there or components throw.
- `PreviewProvider` seed keys are pinned to the fixture's `estimate_id` and address/area/rooms — if `fixture.ts` changes those, update `preview-provider.tsx` to match (else fetch-coupled cards re-floor).
- Synth scan re-includes Next route/layout/error files on every build → `componentSrcMap` nulls (13 entries) must persist. New app-router pages would need adding.
- `.d.ts` props are weak (`[key:string]:unknown`) — synth mode has no built types. Real prop contracts live in each component's source `interface Props`. A real `tsup`/`tsc` lib build would fix this (recommend if the agent needs strong API contracts).
- Grades clear on any `cfg.provider`/preview-affecting config change (expected) — re-grade from fresh sheets.