Migrate OSM cache to localForage/IndexedDB

We don't want to hit limits with localStorage, and it's non-blocking

tests/helpers/index.js

@@ -4,6 +4,7 @@ import {
   setupTest as upstreamSetupTest,
 } from 'ember-qunit';
 import { setupNostrMocks } from './mock-nostr';
+import { setupLocalForageMock } from './mock-local-forage';
 import sinon from 'sinon';
 
 function setupMapStyleMocks(hooks) {
@@ -98,6 +99,7 @@ function setupMapStyleMocks(hooks) {
 function setupApplicationTest(hooks, options) {
   upstreamSetupApplicationTest(hooks, options);
   setupNostrMocks(hooks);
+  setupLocalForageMock(hooks);
   setupMapStyleMocks(hooks);
 
   // Additional setup for application tests can be done here.
@@ -119,6 +121,7 @@ function setupApplicationTest(hooks, options) {
 function setupRenderingTest(hooks, options) {
   upstreamSetupRenderingTest(hooks, options);
   setupNostrMocks(hooks);
+  setupLocalForageMock(hooks);
 
   // Additional setup for rendering tests can be done here.
 }
@@ -126,6 +129,7 @@ function setupRenderingTest(hooks, options) {
 function setupTest(hooks, options) {
   upstreamSetupTest(hooks, options);
   setupNostrMocks(hooks);
+  setupLocalForageMock(hooks);
 
   // Additional setup for unit tests can be done here.
 }

tests/helpers/mock-local-forage.js

@@ -0,0 +1,59 @@
+import Service from '@ember/service';
+
+/**
+ * In-memory mock of the `localForage` service for tests. Uses per-store
+ * `Map`s so tests stay isolated from real IndexedDB state and stay
+ * deterministic.
+ *
+ * Mirrors the real service's interface: `get/set/remove/keys/clear/iterate`.
+ */
+export class MockLocalForageService extends Service {
+  _stores = new Map();
+
+  _store(name) {
+    let store = this._stores.get(name);
+    if (!store) {
+      store = new Map();
+      this._stores.set(name, store);
+    }
+    return store;
+  }
+
+  async get(storeName, key) {
+    const store = this._store(storeName);
+    return store.has(key) ? store.get(key) : null;
+  }
+
+  async set(storeName, key, value) {
+    this._store(storeName).set(key, value);
+    return value;
+  }
+
+  async remove(storeName, key) {
+    this._store(storeName).delete(key);
+  }
+
+  async keys(storeName) {
+    return [...this._store(storeName).keys()];
+  }
+
+  async clear(storeName) {
+    this._store(storeName).clear();
+  }
+
+  async iterate(storeName, fn) {
+    let result;
+    let idx = 0;
+    for (const [key, value] of this._store(storeName)) {
+      result = fn(value, key, idx);
+      idx++;
+    }
+    return result;
+  }
+}
+
+export function setupLocalForageMock(hooks) {
+  hooks.beforeEach(function () {
+    this.owner.register('service:localForage', MockLocalForageService);
+  });
+}