skip Nominatim lookups when the server has none configured

Add GET /api/geocode/status ({configured}), like /api/overpass/status. The outline client and the last-resort place search ask it once per page and send no lookup a server without a Nominatim endpoint would refuse, so a default install no longer logs a 503 on its first named landmark or grounds ask. An older server or a failed probe leaves the capability unknown and lookups proceed as before.

src/search/defaults.js

@@ -2,6 +2,7 @@ import { createNominatimProvider } from './nominatim.js';
 import { createGeospatialServices } from './geospatial.js';
 import { createHttpGeospatialProvider } from './http.js';
 import { createPlaceSearch } from './placeSearch.js';
+import { createNominatimStatus } from '../sources/nominatimStatus.js';
 import { createGoogleGeocoder } from './google.js';
 import { createPhotonGeocoder } from '../keylessGeocoder.js';
 import { createCoordinateGeocoder } from './coordinateGeocoder.js';
@@ -28,6 +29,9 @@ export function createDefaultPlaceSearch({
 } = {}) {
   if (geocoding && geocoding.provider !== 'nominatim')
     throw new TypeError('Unsupported geocoding provider');
+  const nominatimConfigured = endpoints.nominatim
+    ? null
+    : createNominatimStatus({ fetchImpl });
   const selected = geocoding
     ? createNominatimProvider({ ...geocoding, fetchImpl })
     : null;
@@ -74,7 +78,13 @@ export function createDefaultPlaceSearch({
             // neither of the two above did. It speaks the same result shape, so it
             // rides the existing Google adapter rather than needing its own.
             createGoogleGeocoder({
-              request(query, { bias, signal }) {
+              async request(query, { bias, signal }) {
+                // The app's own route says up front when Nominatim is off.
+                if (
+                  nominatimConfigured &&
+                  (await nominatimConfigured()) === false
+                )
+                  return null;
                 const params = new URLSearchParams({ q: query });
                 if (bias) params.set('bounds', bias);
                 return fetchImpl(

src/search/photonSetting.test.mjs

@@ -30,3 +30,26 @@ test('place search follows the Photon setting', async () => {
   const off = await hosts({ photon: null });
   assert.ok(!off.some((host) => host.includes('photon')), off.join(','));
 });
+
+test('the last-resort route is skipped when the server reports Nominatim unconfigured', async () => {
+  const run = async (configured) => {
+    const asked = [];
+    const search = createDefaultPlaceSearch({
+      endpoints: { photon: null },
+      fetchImpl: async (url) => {
+        const path = new URL(String(url), 'http://local.test').pathname;
+        asked.push(path);
+        if (path === '/api/geocode/status')
+          return Response.json({ configured });
+        return Response.json({ status: 'ZERO_RESULTS', results: [] });
+      },
+    });
+    await search.geocode(`nowhere-nominatim-${configured}`);
+    return asked;
+  };
+  const off = await run(false);
+  assert.ok(off.includes('/api/geocode/status'));
+  assert.ok(!off.includes('/api/geocode'), off.join(','));
+  const on = await run(true);
+  assert.ok(on.includes('/api/geocode'), on.join(','));
+});