fix: warn before leaving unsaved map drafts

frontend/src/pages/LocationMapManager.jsx

@@ -1,5 +1,5 @@
 import { useCallback, useContext, useEffect, useRef, useState } from "react";
-import { useLocation, useNavigate, useParams } from "react-router-dom";
+import { useBeforeUnload, useLocation, useNavigate, useParams } from "react-router-dom";
 import {
   createBlankLocationMap,
   createLocationMapFromZones,
@@ -79,12 +79,22 @@ export default function LocationMapManager() {
     ? itemsForZone(mapState?.items || [], selectedObject.zone_id, filters, username)
     : [];
   const visibleUnmappedItems = unmappedItems(mapState?.items || [], filters, username);
+  const shouldGuardLeave = canManage && hasUnsavedChanges;
 
   const mapSize = {
     width: mapDraft.width || activeMap?.width || DEFAULT_MAP_SIZE.width,
     height: mapDraft.height || activeMap?.height || DEFAULT_MAP_SIZE.height,
   };
 
+  useBeforeUnload(
+    useCallback((event) => {
+      if (!shouldGuardLeave) return;
+      event.preventDefault();
+      event.returnValue = "";
+    }, [shouldGuardLeave]),
+    { capture: true }
+  );
+
   const syncMapDraftFromState = useCallback((nextState, nextMode, nextPreviewDraft) => {
     const nextMap = mapForMode(nextState, nextMode, nextPreviewDraft);
     const nextObjects = objectsForMode(nextState, nextMode, nextPreviewDraft);
@@ -435,12 +445,12 @@ export default function LocationMapManager() {
   }, [navigate, returnPath]);
 
   const handleBack = useCallback(() => {
-    if (hasUnsavedChanges && canManage) {
+    if (shouldGuardLeave) {
       setPendingLeave(true);
       return;
     }
     performBackNavigation();
-  }, [canManage, hasUnsavedChanges, performBackNavigation]);
+  }, [performBackNavigation, shouldGuardLeave]);
 
   if (!hasLoaded || householdLoading || loading) {
     return (

frontend/tests/location-map-manager.spec.ts

@@ -669,6 +669,70 @@ test("admin save progress locks draft controls", async ({ page }) => {
   await expect(page.getByRole("button", { name: "Save Draft" })).toBeDisabled();
 });
 
+test("admin hard navigation warns when draft edits are unsaved", async ({ page }) => {
+  await mockMapShell(page);
+
+  const mapState = draftMapState([
+    {
+      id: 1371,
+      location_map_id: 900,
+      zone_id: 501,
+      zone_name: "Bakery",
+      type: "zone",
+      label: "Bakery",
+      x: 40,
+      y: 40,
+      width: 260,
+      height: 160,
+      rotation: 0,
+      locked: false,
+      visible: true,
+      sort_order: 1,
+    },
+  ], true);
+
+  await page.route("**/households/1/locations/10/map", async (route) => {
+    await route.fulfill({
+      status: 200,
+      contentType: "application/json",
+      body: JSON.stringify(mapState),
+    });
+  });
+
+  await page.goto("/stores/100/locations/10/map");
+
+  const cleanBeforeUnload = await page.evaluate(() => {
+    const event = new Event("beforeunload", { cancelable: true });
+    const dispatchResult = window.dispatchEvent(event);
+    return {
+      defaultPrevented: event.defaultPrevented,
+      dispatchResult,
+    };
+  });
+  expect(cleanBeforeUnload).toEqual({
+    defaultPrevented: false,
+    dispatchResult: true,
+  });
+
+  await page.getByRole("button", { name: "Continue Editing" }).click();
+  await page.getByRole("button", { name: "Edit Objects" }).click();
+  await page.locator(".location-map-object", { hasText: "Bakery" }).locator("rect").first().click();
+  await page.getByRole("textbox", { name: "Label" }).fill("Hard Navigation Bakery");
+
+  const dirtyBeforeUnload = await page.evaluate(() => {
+    const event = new Event("beforeunload", { cancelable: true });
+    const dispatchResult = window.dispatchEvent(event);
+    return {
+      defaultPrevented: event.defaultPrevented,
+      dispatchResult,
+    };
+  });
+  expect(dirtyBeforeUnload).toEqual({
+    defaultPrevented: true,
+    dispatchResult: false,
+  });
+});
+
 test("admin publish saves pending map edits before publishing", async ({ page }) => {
   await mockMapShell(page);