feat(web): page-driven breadcrumb context + header render + objects wiring (#54)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/objects/objects-page.tsx

@@ -6,6 +6,7 @@ import { X } from "lucide-react";
 import { ObjectsTable } from "./objects-table";
 import { useMediaQuery } from "../lib/use-media-query";
 import { useDocumentTitle } from "../lib/use-document-title";
+import { useBreadcrumb } from "../shell/use-breadcrumb";
 import { PageTitle } from "@/components/ui/page-title";
 
 const ObjectDetailDrawer = lazy(() =>
@@ -26,6 +27,7 @@ export function ObjectsPage() {
   const isWide = useMediaQuery("(min-width: 1024px)");
 
   useDocumentTitle(t("nav.objects"));
+  useBreadcrumb([{ label: t("nav.objects") }]);
 
   const closeDetail = () => navigate(`/objects?${searchParams}`);
 

web/src/shell/app-shell.tsx

@@ -6,6 +6,8 @@ import { Button } from "@/components/ui/button";
 import { LangSwitch } from "./lang-switch";
 import { ThemeSwitch } from "./theme-switch";
 import { Sidebar } from "./sidebar";
+import { BreadcrumbProvider } from "./breadcrumb-provider";
+import { Breadcrumb } from "./breadcrumb";
 
 export function AppShell() {
   const { t } = useTranslation();
@@ -20,9 +22,10 @@ export function AppShell() {
   return (
     <div className="flex min-h-screen">
       <Sidebar />
+      <BreadcrumbProvider>
         <div className="flex flex-1 flex-col">
           <header className="flex items-center gap-4 border-b px-4 py-2">
-          <div className="flex-1" />
+            <Breadcrumb />
             <ThemeSwitch />
             <LangSwitch />
             <Button variant="ghost" size="sm" onClick={onSignOut}>
@@ -33,6 +36,7 @@ export function AppShell() {
             <Outlet />
           </main>
         </div>
+      </BreadcrumbProvider>
     </div>
   );
 }

web/src/shell/breadcrumb-context.ts

@@ -0,0 +1,17 @@
+import { createContext, useContext } from "react";
+
+export type BreadcrumbItem = { label: string; to?: string };
+
+type BreadcrumbContextValue = {
+  trail: BreadcrumbItem[];
+  setTrail: (trail: BreadcrumbItem[]) => void;
+};
+
+export const BreadcrumbContext = createContext<BreadcrumbContextValue>({
+  trail: [],
+  setTrail: () => {},
+});
+
+export function useBreadcrumbTrail(): BreadcrumbItem[] {
+  return useContext(BreadcrumbContext).trail;
+}

web/src/shell/breadcrumb-provider.tsx

@@ -0,0 +1,12 @@
+import { useState, type ReactNode } from "react";
+
+import { BreadcrumbContext, type BreadcrumbItem } from "./breadcrumb-context";
+
+export function BreadcrumbProvider({ children }: { children: ReactNode }) {
+  const [trail, setTrail] = useState<BreadcrumbItem[]>([]);
+  return (
+    <BreadcrumbContext.Provider value={{ trail, setTrail }}>
+      {children}
+    </BreadcrumbContext.Provider>
+  );
+}

web/src/shell/breadcrumb.test.tsx

@@ -0,0 +1,26 @@
+import { expect, test } from "vitest";
+import { screen } from "@testing-library/react";
+import { renderApp } from "../test/render";
+import { BreadcrumbProvider } from "./breadcrumb-provider";
+import { Breadcrumb } from "./breadcrumb";
+import { useBreadcrumb } from "./use-breadcrumb";
+
+function Setter() {
+  useBreadcrumb([
+    { label: "Objects", to: "/objects" },
+    { label: "LM-0042" },
+  ]);
+  return null;
+}
+
+test("renders the trail with a link on non-leaf crumbs", async () => {
+  renderApp(
+    <BreadcrumbProvider>
+      <Breadcrumb />
+      <Setter />
+    </BreadcrumbProvider>,
+  );
+  const link = await screen.findByRole("link", { name: "Objects" });
+  expect(link).toHaveAttribute("href", "/objects");
+  expect(screen.getByText("LM-0042")).toBeInTheDocument();
+});

web/src/shell/breadcrumb.tsx

@@ -0,0 +1,30 @@
+import { Fragment } from "react";
+import { Link } from "react-router-dom";
+
+import { useBreadcrumbTrail } from "./breadcrumb-context";
+
+export function Breadcrumb() {
+  const trail = useBreadcrumbTrail();
+  if (trail.length === 0) return <div className="min-w-0 flex-1" />;
+  return (
+    <nav aria-label="Breadcrumb" className="flex min-w-0 flex-1 items-center gap-1 text-sm">
+      {trail.map((item, i) => {
+        const last = i === trail.length - 1;
+        return (
+          <Fragment key={`${item.label}-${i}`}>
+            {i > 0 && <span className="text-muted-foreground">/</span>}
+            {item.to && !last ? (
+              <Link to={item.to} className="truncate text-muted-foreground hover:text-foreground">
+                {item.label}
+              </Link>
+            ) : (
+              <span className={last ? "truncate text-foreground" : "truncate text-muted-foreground"}>
+                {item.label}
+              </span>
+            )}
+          </Fragment>
+        );
+      })}
+    </nav>
+  );
+}

web/src/shell/use-breadcrumb.ts

@@ -0,0 +1,12 @@
+import { useContext, useEffect } from "react";
+
+import { BreadcrumbContext, type BreadcrumbItem } from "./breadcrumb-context";
+
+export function useBreadcrumb(trail: BreadcrumbItem[]): void {
+  const { setTrail } = useContext(BreadcrumbContext);
+  const key = trail.map((i) => `${i.label} ${i.to ?? ""}`).join("");
+  useEffect(() => {
+    setTrail(trail);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [key, setTrail]);
+}