feat(service-credential-tester): slice 2 — Test button + gating (shared ServiceTestPanel)

Presentational ServiceTestPanel (props-driven, no internal hooks) wired into
both CreateServiceDialog (ServicesPage.tsx) and ServiceConfigEditor
(Settings.tsx). Parent owns testResult + saveAnyway state; store-previous
pattern resets on input change (avoids setState-in-effect). Create/Save
button gated on testPassed || saveAnyway. 7 panel tests (button states,
success/failure pills, checkbox toggle). All gates: 158 vitest, build exit 0,
lint 0 errors, 362 backend pytest (regression).

frontend/src/components/ServiceTestPanel.tsx

@@ -0,0 +1,72 @@
+import { Alert, AlertDescription } from "@/components/ui/alert";
+import { Button } from "@/components/ui/button";
+import type { ServiceTestResult } from "../types";
+
+interface Props {
+	/** Current test result (null = not tested yet). Parent clears this when the form input changes. */
+	result: ServiceTestResult | null;
+	/** Whether the test mutation is in-flight. */
+	isPending: boolean;
+	/** Whether the "Save anyway" checkbox is checked. */
+	saveAnyway: boolean;
+	/** Fired when the user clicks "Test credentials". */
+	onTest: () => void;
+	/** Fired when the "Save anyway" checkbox toggles. */
+	onSaveAnywayChange: (checked: boolean) => void;
+	/** Disable the Test button (e.g. no draft yet). */
+	disabled?: boolean;
+}
+
+/**
+ * Shared "Test credentials" panel used by both the add-service dialog and the
+ * edit-service panel. Purely presentational — the parent owns the test result
+ * + saveAnyway state and the mutation hook. This avoids setState-in-effect
+ * issues with clearing the result on input change (the parent uses the
+ * React-recommended "store previous prop" pattern instead).
+ */
+export function ServiceTestPanel({
+	result,
+	isPending,
+	saveAnyway,
+	onTest,
+	onSaveAnywayChange,
+	disabled,
+}: Props) {
+	const testPassed = result?.ok === true;
+
+	return (
+		<div className="flex flex-col gap-2">
+			<Button
+				variant="outline"
+				size="sm"
+				onClick={onTest}
+				disabled={isPending || disabled}
+				className="mobile-touch-target"
+			>
+				{isPending ? "Testing…" : "Test credentials"}
+			</Button>
+			{result ? (
+				<Alert variant={result.ok ? "default" : "destructive"}>
+					<AlertDescription>
+						{result.ok
+							? `✓ Connected${result.evidence ? ` — ${result.evidence}` : ""}`
+							: `✗ ${result.detail}`}
+					</AlertDescription>
+				</Alert>
+			) : null}
+			<label className="flex items-center gap-2 text-xs text-muted-foreground">
+				<input
+					type="checkbox"
+					checked={saveAnyway}
+					onChange={(e) => onSaveAnywayChange(e.target.checked)}
+				/>
+				Save anyway (skip test)
+			</label>
+			{!testPassed && !saveAnyway ? (
+				<p className="text-xs text-muted-foreground">
+					Test credentials or check "Save anyway" to enable the save button.
+				</p>
+			) : null}
+		</div>
+	);
+}

frontend/src/components/__tests__/ServiceTestPanel.test.tsx

@@ -0,0 +1,115 @@
+import { describe, it, expect, vi } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import { ServiceTestPanel } from "../ServiceTestPanel";
+import type { ServiceTestResult } from "../../types";
+
+function noop() {}
+
+describe("ServiceTestPanel", () => {
+	it("renders the Test credentials button", () => {
+		render(
+			<ServiceTestPanel
+				result={null}
+				isPending={false}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		expect(screen.getByText("Test credentials")).toBeTruthy();
+	});
+
+	it("shows Testing… and disables button while pending", () => {
+		render(
+			<ServiceTestPanel
+				result={null}
+				isPending={true}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		expect(screen.getByText("Testing…")).toBeTruthy();
+		expect(screen.getByText("Testing…")).toBeDisabled();
+	});
+
+	it("renders green ✓ Connected pill with evidence on success", () => {
+		const result: ServiceTestResult = {
+			ok: true,
+			detail: "ok",
+			evidence: "v4.5.0",
+		};
+		render(
+			<ServiceTestPanel
+				result={result}
+				isPending={false}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		expect(screen.getByText(/✓ Connected — v4.5.0/)).toBeTruthy();
+	});
+
+	it("renders red ✗ pill with detail on failure", () => {
+		const result: ServiceTestResult = {
+			ok: false,
+			detail: "Authentication failed",
+			evidence: null,
+		};
+		render(
+			<ServiceTestPanel
+				result={result}
+				isPending={false}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		expect(screen.getByText(/✗ Authentication failed/)).toBeTruthy();
+	});
+
+	it("fires onTest when Test credentials is clicked", () => {
+		const onTest = vi.fn();
+		render(
+			<ServiceTestPanel
+				result={null}
+				isPending={false}
+				saveAnyway={false}
+				onTest={onTest}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		fireEvent.click(screen.getByText("Test credentials"));
+		expect(onTest).toHaveBeenCalledOnce();
+	});
+
+	it("fires onSaveAnywayChange when checkbox is toggled", () => {
+		const onSaveAnywayChange = vi.fn();
+		render(
+			<ServiceTestPanel
+				result={null}
+				isPending={false}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={onSaveAnywayChange}
+			/>,
+		);
+		const checkbox = screen.getByRole("checkbox");
+		fireEvent.click(checkbox);
+		expect(onSaveAnywayChange).toHaveBeenCalledWith(true);
+	});
+
+	it("renders the Save anyway checkbox", () => {
+		render(
+			<ServiceTestPanel
+				result={null}
+				isPending={false}
+				saveAnyway={false}
+				onTest={noop}
+				onSaveAnywayChange={noop}
+			/>,
+		);
+		expect(screen.getByRole("checkbox")).toBeTruthy();
+	});
+});