feat(api): add scoped multi-instance query client

Adds createScopedClient() — an openapi-fetch client bound to a specific
Instance (rather than the active one in localStorage) — and the
useScoped* TanStack Query hooks (workspaces, peers, peer representation,
peer card) with per-instance query-key isolation so caches never collide
across instances.

Foundation for multi-instance features (seed kits, desktop
auto-discover) that read from non-active instances.

Co-authored-by: Ben Sheridan-Edwards <BenSheridanEdwards@users.noreply.github.com>

packages/web/src/api/scopedClient.ts

@@ -0,0 +1,18 @@
+import createClient from "openapi-fetch";
+import type { Instance } from "@/lib/config";
+import { httpFetch } from "@/lib/http";
+import type { paths } from "./schema.d.ts";
+
+export type ScopedClient = ReturnType<typeof createClient<paths>>;
+
+/**
+ * Create an openapi-fetch client bound to a specific instance. Use for views
+ * that need to query non-active instances (e.g. side-by-side comparison).
+ * For single-instance access, prefer `client.current` which tracks the active
+ * instance via localStorage.
+ */
+export function createScopedClient(instance: Instance): ScopedClient {
+	const headers: Record<string, string> = { "Content-Type": "application/json" };
+	if (instance.token) headers.Authorization = `Bearer ${instance.token}`;
+	return createClient<paths>({ baseUrl: instance.baseUrl, headers, fetch: httpFetch });
+}