Disable update check and notification in SaaS mode (#6863)

# Description of Changes

In SaaS mode the self-hosted "Update Available" notification could still
appear and the update-check code (external call to
`supabase.stirling.com/functions/v1/updates`) still ran, even though the
cloud owns app versioning. The web `UpdateStartupPopup` was already
SaaS-gated via a null override, but two other paths were not:

- **Desktop app in SaaS connection mode** - `useDesktopUpdatePopup()`
ran its startup check and rendered the `UpdateModal` regardless of
connection mode, so a self-hosted update popup appeared while connected
to SaaS.
- **Settings → General** - the core `GeneralSection` fired
`checkForUpdate()` on mount unconditionally, even when the update
section was hidden (as SaaS does), so the external call still ran.

**What changed**

- `useDesktopUpdatePopup.ts` - the startup timer now bails out
immediately when `connectionModeService.getCurrentMode() === "saas"`. No
mode lookup, no external fetch, no modal.
- `core/GeneralSection.tsx` - the mount `checkForUpdate()` now returns
early when `hideUpdateSection` is set, so hiding the section (web SaaS,
managed-disabled desktop) also stops the external call.
- `desktop/GeneralSection.tsx` - passes `hideUpdateSection` when
`useSaaSMode()` is true, which (via the above) suppresses the settings
check in desktop-SaaS too.

**Why** - in SaaS the update check should never be called and no update
notification should be shown; the cloud handles versioning.

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [x] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

frontend/editor/src/core/components/shared/config/configSections/GeneralSection.tsx

@@ -112,12 +112,14 @@ const GeneralSection: React.FC<GeneralSectionProps> = ({
   // falling back to the backend version
   const currentVersion = appVersion ?? config?.appVersion ?? null;
 
-  // Check for updates on mount
+  // Check for updates on mount — skipped when the update UI is hidden (SaaS
+  // build, managed-disabled desktop) so no external update call ever fires.
   useEffect(() => {
+    if (hideUpdateSection) return;
     if (currentVersion) {
       checkForUpdate();
     }
-  }, [currentVersion, config?.machineType]);
+  }, [currentVersion, config?.machineType, hideUpdateSection]);
 
   const checkForUpdate = async () => {
     if (!currentVersion) return;

frontend/editor/src/desktop/components/shared/config/configSections/GeneralSection.tsx

@@ -4,6 +4,7 @@ import { useTranslation } from "react-i18next";
 import CoreGeneralSection from "@core/components/shared/config/configSections/GeneralSection";
 import { DefaultAppSettings } from "@app/components/shared/config/configSections/DefaultAppSettings";
 import { useDesktopInstall } from "@app/hooks/useDesktopInstall";
+import { useSaaSMode } from "@app/hooks/useSaaSMode";
 import {
   desktopUpdateService,
   type UpdateMode,
@@ -22,6 +23,9 @@ import {
 const GeneralSection: React.FC = () => {
   const { t } = useTranslation();
   const install = useDesktopInstall();
+  // In SaaS connection mode the cloud owns app versioning — hide the update
+  // section (which also stops the core auto-check from firing).
+  const isSaaSMode = useSaaSMode();
   const [updateModeInfo, setUpdateModeInfo] = useState<UpdateModeInfo>({
     mode: "prompt",
     locked: false,
@@ -93,7 +97,8 @@ const GeneralSection: React.FC = () => {
       )}
       <CoreGeneralSection
         hideUpdateSection={
-          updateModeInfo.mode === "disabled" && updateModeInfo.locked
+          isSaaSMode ||
+          (updateModeInfo.mode === "disabled" && updateModeInfo.locked)
         }
         desktopInstall={{
           state: install.state,

frontend/editor/src/desktop/hooks/useDesktopUpdatePopup.test.ts

@@ -9,6 +9,7 @@ const getVersionMock = vi.fn();
 const getUpdateModeMock = vi.fn();
 const canInstallUpdatesMock = vi.fn();
 const getUpdateSummaryMock = vi.fn();
+const getCurrentModeMock = vi.fn();
 
 vi.mock("@tauri-apps/api/core", () => ({
   invoke: (cmd: string, args?: unknown) => invokeMock(cmd, args),
@@ -36,6 +37,12 @@ vi.mock("@app/services/desktopUpdateService", () => ({
   },
 }));
 
+vi.mock("@app/services/connectionModeService", () => ({
+  connectionModeService: {
+    getCurrentMode: () => getCurrentModeMock(),
+  },
+}));
+
 import { useDesktopUpdatePopup } from "@app/hooks/useDesktopUpdatePopup";
 
 /** Flush pending microtasks so awaited promises settle. */
@@ -74,8 +81,11 @@ describe("useDesktopUpdatePopup — auto mode", () => {
     getUpdateModeMock.mockReset();
     canInstallUpdatesMock.mockReset();
     getUpdateSummaryMock.mockReset();
+    getCurrentModeMock.mockReset();
 
-    // Defaults: auto mode, update available, install permitted.
+    // Defaults: local (non-SaaS) connection, auto mode, update available,
+    // install permitted.
+    getCurrentModeMock.mockResolvedValue("local");
     getUpdateModeMock.mockResolvedValue("auto");
     getVersionMock.mockResolvedValue("1.0.0");
     getUpdateSummaryMock.mockResolvedValue({ latest_version: "2.0.0" });
@@ -189,4 +199,18 @@ describe("useDesktopUpdatePopup — auto mode", () => {
     expect(invocations).toContain("download_and_install_update");
     expect(invocations).toContain("restart_app");
   });
+
+  it("skips the update check entirely in SaaS connection mode", async () => {
+    // In SaaS mode the cloud owns versioning — the self-hosted update check
+    // must never run: no mode lookup, no external summary fetch, no install.
+    getCurrentModeMock.mockResolvedValue("saas");
+
+    await runStartup();
+
+    expect(getUpdateModeMock).not.toHaveBeenCalled();
+    expect(getUpdateSummaryMock).not.toHaveBeenCalled();
+    const invocations = invokeMock.mock.calls.map((c) => c[0]);
+    expect(invocations).not.toContain("download_and_install_update");
+    expect(invocations).not.toContain("restart_app");
+  });
 });

frontend/editor/src/desktop/hooks/useDesktopUpdatePopup.ts

@@ -6,6 +6,7 @@ import {
   desktopUpdateService,
   type CanInstallResult,
 } from "@app/services/desktopUpdateService";
+import { connectionModeService } from "@app/services/connectionModeService";
 
 const SNOOZE_KEY = "stirling-pdf-updater:snoozedUntil";
 const STARTUP_DELAY_MS = 15_000;
@@ -72,6 +73,10 @@ export function useDesktopUpdatePopup() {
     hasChecked.current = true;
 
     const timer = setTimeout(async () => {
+      // In SaaS connection mode the cloud owns app versioning — the self-hosted
+      // update check + popup must never run (no external call, no modal).
+      if ((await connectionModeService.getCurrentMode()) === "saas") return;
+
       let mode: Awaited<ReturnType<typeof desktopUpdateService.getUpdateMode>> =
         "prompt";
       try {