refactor: detect platform via APIService.isMobile() instead of Platform.isDesktopApp

Address the maintainer review on #949: determine the platform through the
plugin's own service layer (services.API.isMobile()) rather than Obsidian's
Platform API directly, matching the existing call in ObsidianLiveSyncSettingTab.
Applies to both PR-introduced sites: the runtime guard (ModuleObsidianEvents)
and the settings-pane toggle (PaneSyncSettings).

The TFile import becomes type-only so deps.ts is no longer pulled at runtime;
the unit test drives the platform through the services.API.isMobile() mock.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/modules/essentialObsidian/ModuleObsidianEvents.ts

@@ -2,7 +2,7 @@ import { AbstractObsidianModule } from "../AbstractObsidianModule.ts";
 import { EVENT_FILE_RENAMED, EVENT_LEAF_ACTIVE_CHANGED, eventHub } from "../../common/events.js";
 import { LOG_LEVEL_NOTICE, LOG_LEVEL_VERBOSE } from "octagonal-wheels/common/logger";
 import { scheduleTask } from "octagonal-wheels/concurrency/task";
-import { Platform, type TFile } from "../../deps.ts";
+import type { TFile } from "../../deps.ts";
 import { fireAndForget } from "octagonal-wheels/promises";
 import { type FilePathWithPrefix } from "../../lib/src/common/types.ts";
 import { reactive, reactiveSource, type ReactiveSource } from "octagonal-wheels/dataobject/reactive";
@@ -146,7 +146,7 @@ export class ModuleObsidianEvents extends AbstractObsidianModule {
         const keepActiveInBackground =
             this.settings.keepReplicationActiveInBackground &&
             (this.settings.liveSync || this.settings.periodicReplication) &&
-            Platform.isDesktopApp;
+            !this.services.API.isMobile();
 
         if (isHidden) {
             if (!keepActiveInBackground) await this.services.appLifecycle.onSuspending();

src/modules/essentialObsidian/ModuleObsidianEvents.unit.spec.ts

@@ -1,11 +1,5 @@
-import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { describe, it, expect, vi, afterEach } from "vitest";
 
-// Unit tests stub out `obsidian`, so deps.ts (which re-exports from it) can't be loaded for real.
-// ModuleObsidianEvents only needs `Platform` from deps at runtime; provide a mutable stub so each
-// test can choose desktop vs mobile.
-vi.mock("../../deps.ts", () => ({ Platform: { isDesktopApp: true } }));
-
-import { Platform } from "../../deps.ts";
 import { ModuleObsidianEvents } from "./ModuleObsidianEvents";
 import { DEFAULT_SETTINGS, REMOTE_COUCHDB } from "@lib/common/types";
 
@@ -15,6 +9,8 @@ type SetupOptions = {
     isLastHidden?: boolean;
     hasFocus?: boolean;
     isSuspended?: boolean;
+    // Platform is read via services.API.isMobile(); default desktop (false) so the feature applies.
+    isMobile?: boolean;
 };
 
 function setup(opts: SetupOptions) {
@@ -35,6 +31,7 @@ function setup(opts: SetupOptions) {
                 registerWindow: vi.fn(),
                 addRibbonIcon: vi.fn(),
                 registerProtocolHandler: vi.fn(),
+                isMobile: vi.fn(() => opts.isMobile ?? false),
             },
             setting: { saveSettingData: vi.fn(async () => undefined) },
             appLifecycle,
@@ -60,15 +57,10 @@ function setup(opts: SetupOptions) {
 }
 
 describe("watchWindowVisibilityAsync — keepReplicationActiveInBackground", () => {
-    beforeEach(() => {
-        (Platform as any).isDesktopApp = true;
-    });
-
     afterEach(() => {
-        // The handler reads a global `activeWindow`; the Platform mock is module-scoped. Both would
-        // otherwise leak into sibling spec files running in the same worker, so reset them here.
+        // The handler reads a global `activeWindow`; clear it so it doesn't leak into sibling spec
+        // files running in the same worker.
         delete (globalThis as any).activeWindow;
-        (Platform as any).isDesktopApp = true;
     });
 
     it("does NOT suspend on hide when enabled in LiveSync mode on the desktop app", async () => {
@@ -162,11 +154,11 @@ describe("watchWindowVisibilityAsync — keepReplicationActiveInBackground", ()
         expect(appLifecycle.onResumed).toHaveBeenCalledTimes(1);
     });
 
-    it("does not apply on a non-desktop app even if the flag is set", async () => {
-        (Platform as any).isDesktopApp = false;
+    it("does not apply on mobile even if the flag is set", async () => {
         const { module, appLifecycle } = setup({
             settings: { keepReplicationActiveInBackground: true, liveSync: true },
             hidden: true,
+            isMobile: true,
         });
         await module.watchWindowVisibilityAsync();
         expect(appLifecycle.onSuspending).toHaveBeenCalledTimes(1);

src/modules/features/SettingDialogue/PaneSyncSettings.ts

@@ -11,7 +11,6 @@ import { EVENT_REQUEST_COPY_SETUP_URI, eventHub } from "../../../common/events.t
 import type { ObsidianLiveSyncSettingTab } from "./ObsidianLiveSyncSettingTab.ts";
 import type { PageFunctions } from "./SettingPane.ts";
 import { visibleOnly } from "./SettingPane.ts";
-import { Platform } from "../../../deps.ts";
 export function paneSyncSettings(
     this: ObsidianLiveSyncSettingTab,
     paneEl: HTMLElement,
@@ -193,7 +192,7 @@ export function paneSyncSettings(
         // Desktop app only, and only for the sync modes that keep a background replication channel
         // (LiveSync and Periodic). Ignored on mobile, where suspending preserves battery. The
         // visibility predicate mirrors the runtime guard in ModuleObsidianEvents.
-        if (Platform.isDesktopApp) {
+        if (!this.services.API.isMobile()) {
             new Setting(paneEl).setClass("wizardHidden").autoWireToggle("keepReplicationActiveInBackground", {
                 onUpdate: visibleOnly(
                     () => this.isConfiguredAs("syncMode", "LIVESYNC") || this.isConfiguredAs("syncMode", "PERIODIC")