admin: live query detail becomes a modal, live/history and period pickers become tabs and radios, client delete confirms in a dialog

the streamed-query detail panel is now a rac modal dialog with focus containment and restore. the live/history switch is rac tabs driven by the url, the overview period picker is a rac radio group, and the clients delete flow uses the shared confirm dialog; an authority turn keeps the dialog open and withdraws only the destructive action.

admin/src/features/overview/OverviewPage.test.tsx

@@ -189,7 +189,7 @@ test("a request in flight leaves the heading and the picker usable behind one lo
 	renderApp();
 
 	await screen.findByRole("heading", { name: "Overview", level: 1 });
-	expect(screen.getByRole("button", { name: "1h" })).toBeTruthy();
+	expect(screen.getByRole("radio", { name: "1h" })).toBeTruthy();
 	// One loading state for the whole page, not one per panel.
 	const loading = await screen.findByText("Loading…");
 	expect(loading.getAttribute("role")).toBe("status");
@@ -335,14 +335,23 @@ test("an empty window says so in every panel instead of drawing nothing", async
 test("a deep link opens on the period it names", async () => {
 	renderApp("/overview?period=1h");
 	await screen.findByText("12");
-	expect(screen.getByRole("button", { name: "1h" }).getAttribute("aria-pressed")).toBe("true");
-	expect(screen.getByRole("button", { name: "24h" }).getAttribute("aria-pressed")).toBe("false");
+	// One radio group named Period, holding the four periods and exactly one
+	// selection: the segmented picker is a single choice, not four toggles.
+	const picker = within(screen.getByRole("radiogroup", { name: "Period" }));
+	expect(picker.getAllByRole("radio").map((radio) => radio.getAttribute("value"))).toEqual([
+		"1h",
+		"24h",
+		"7d",
+		"30d",
+	]);
+	expect(picker.getByRole("radio", { name: "1h", checked: true })).toBeTruthy();
+	expect(picker.getByRole("radio", { name: "24h", checked: false })).toBeTruthy();
 });
 
 test("a period the API does not have falls back to the default without carrying it in the url", async () => {
 	const router = renderApp("/overview?period=90d");
 	await screen.findByText("1,000");
-	expect(screen.getByRole("button", { name: "24h" }).getAttribute("aria-pressed")).toBe("true");
+	expect(screen.getByRole("radio", { name: "24h", checked: true })).toBeTruthy();
 	expect(router.state.location.search).toEqual({});
 });
 
@@ -350,7 +359,7 @@ test("the picker rescopes every panel and writes the period into the url", async
 	const router = renderApp();
 	await screen.findByText("1,000");
 
-	fireEvent.click(screen.getByRole("button", { name: "1h" }));
+	fireEvent.click(screen.getByRole("radio", { name: "1h" }));
 
 	await screen.findByText("12");
 	await waitFor(() => expect(router.state.location.search).toEqual({ period: "1h" }));
@@ -369,7 +378,7 @@ test("a failed request is one error for the whole page, stated once and retryabl
 	expect(screen.getAllByRole("button", { name: "Retry" })).toHaveLength(1);
 	// The heading and the picker survive it, so the reader can rescope or retry.
 	expect(screen.getByRole("heading", { name: "Overview", level: 1 })).toBeTruthy();
-	expect(screen.getByRole("button", { name: "1h" })).toBeTruthy();
+	expect(screen.getByRole("radio", { name: "1h" })).toBeTruthy();
 	expect(screen.queryByText("Something went wrong")).toBeNull();
 
 	failing = false;