updated claude.md

CLAUDE.md

@@ -1,11 +1,16 @@
 # Claude guidance for this project
 
+## Project conventions
+
+- **Domain language lives in [`CONTEXT.md`](./CONTEXT.md).** Read it before naming or discussing BulkUpload, Portfolio, Property, etc. concepts.
+- **Architectural decisions live in [`docs/adr/`](./docs/adr/).** Read existing ADRs before proposing changes that touch state machines or core flows. Write a new ADR for any decision that's hard to reverse, surprising without context, and the result of a real trade-off.
+
 ## React
 
-- **Avoid `useEffect` and `useMemo`.** Derive values inline, use Server Components + Route Handlers, event handlers. If a hook is genuinely the only option, flag it and ask before using it.
-
-- Instead of raw fetch use useQuery to allow handling of mutations
+- **Avoid `useEffect` and `useMemo`.** Derive values inline, prefer Server Components + Route Handlers, prefer event handlers. If a hook is genuinely the only option, flag it and ask before using it.
+- **Use TanStack Query (`@tanstack/react-query`), not raw `fetch`, for client-side HTTP.** Reads use `useQuery`; writes use `useMutation`. This project is on **v4** — note that `refetchInterval`'s callback signature is `(data, query)`, not v5's `(query)`.
 
 ## Next.js 15 route handlers
 
 - `params` is a `Promise` — type as `{ params: Promise<{ ... }> }` and `await params` before destructuring.
+- Error responses use `{ error: string }` consistently. Don't drift to `{ msg }` or other shapes.