Fix: ServicePage content tabs wrapped in SheetForm on mobile

The reconciliation with mobile-responsive-parity applied the SheetForm
wrapper (designed when ServicePage was config-only) to the ENTIRE
service page, including content tabs. Clicking a nav item like 'Media'
on mobile opened a form sheet with Save/Cancel instead of the tabbed
content browser.

Fix: ServicePage now renders the Tabs skeleton on ALL breakpoints.
Content tabs (Media, Files, Actions, etc.) are operational views, not
forms -- they have their own mobile handling (MobileCardRow, etc.) and
should not be wrapped in a Save/Cancel sheet. The Config tab renders
inline like every other tab.

Removes the isMobile branch + SheetForm wrapper + dead imports
(useIsMobile, SheetForm) + sheetOpen state. 117 tests pass; lint/build
green.

frontend/src/pages/ServicePage.tsx

@@ -20,8 +20,6 @@ import {
 	useServiceInstances,
 	useServiceTypes,
 } from "../hooks/useServices";
-import { useIsMobile } from "../hooks/useIsMobile";
-import { SheetForm } from "@/components/ui/sheet-form";
 import type {
 	ServiceInstance,
 	ServiceInstanceInput,
@@ -99,8 +97,6 @@ export function ServicePage() {
 	const [draftSecrets, setDraftSecrets] = useState<Record<string, string>>({});
 	const [deleteOpen, setDeleteOpen] = useState(false);
 	const [hydrated, setHydrated] = useState(false);
-	const isMobile = useIsMobile();
-	const [sheetOpen, setSheetOpen] = useState(true);
 
 	if (instance && !hydrated) {
 		setName(instance.name);
@@ -149,9 +145,10 @@ export function ServicePage() {
 		setDraftSecrets({});
 	}
 
+
 	const allTabs: ContentTab[] = [OVERVIEW_TAB, ...contentTabs];
 
-	// The config + widgets body, shared between desktop tabs and mobile SheetForm.
+	// The config + widgets body, rendered inside the Config and Widgets tabs.
 	const widgetsContent =
 		binding.widgets.length > 0 ? (
 			<div className="flex flex-col gap-2">
@@ -197,58 +194,6 @@ export function ServicePage() {
 		/>
 	);
 
-	// Mobile: render inside a SheetForm (open on mount; cancel navigates back).
-	if (isMobile) {
-		return (
-			<div className="flex flex-col gap-4">
-				<SheetForm
-					open={sheetOpen}
-					onOpenChange={setSheetOpen}
-					title={name || instance.name}
-					onSave={save}
-					onCancel={() => {
-						setSheetOpen(false);
-						navigate("/services");
-					}}
-					isPending={saveService.isPending}
-					isDirty={
-						name !== instance.name ||
-						enabled !== instance.enabled ||
-						JSON.stringify(draftConfig) !== JSON.stringify(instance.config)
-					}
-				>
-					<div className="flex flex-col gap-6">
-						{allTabs.map((tab) => {
-							const TabComponent = tab.Component;
-							return (
-								<div key={tab.label}>
-									<h3 className="mb-2 text-sm font-semibold text-muted-foreground">
-										{tab.label}
-									</h3>
-									<TabComponent instance={instance} />
-								</div>
-							);
-						})}
-						{widgetsContent}
-						{configBody}
-					</div>
-				</SheetForm>
-				<ConfirmDialog
-					open={deleteOpen}
-					title="Delete service?"
-					message="This removes the service and any widgets that reference it. This cannot be undone."
-					confirmLabel="Delete"
-					onCancel={() => setDeleteOpen(false)}
-					onConfirm={() => {
-						deleteService.mutate(instance.id);
-						setDeleteOpen(false);
-						navigate("/services");
-					}}
-				/>
-			</div>
-		);
-	}
-
 	return (
 		<div className="flex flex-col gap-4">
 			{/* Header + instance switcher */}