fix(diagnostics): Back from a request's lines returns to the view it came from

Every filter change replaced the history entry, so Back after a request or
job pivot left the console altogether (the 0.90 notes promised otherwise).
A pivot follows a link and is its own entry now; the console reads the
landed entry back on popstate. The other filters still adjust in place.

frontend/src/components/AdminLogs.dom.test.tsx

@@ -124,6 +124,42 @@ describe("AdminLogs", () => {
     expect([url.get("lreq"), url.get("lgrp"), url.get("lq")]).toEqual(["req-00000001", null, null]);
   });
 
+  it("Back from a request's lines returns to the view the pivot was made from", async () => {
+    window.history.replaceState({ sfPage: "logs" }, "", "/?page=logs&lgrp=error&lq=boom");
+    const depth = window.history.length;
+    logsMock.mockResolvedValue({ items: [row(1)], accounts: {}, next_cursor: null });
+    renderConsole();
+    await waitFor(() => expect(lines()).toHaveLength(1));
+    fireEvent.click(lines()[0]!);
+    fireEvent.click(screen.getByRole("button", { name: "req-00000001" }));
+    await waitFor(() =>
+      expect(screen.getByText("adminLogs.pivotRequest:req-00000001")).toBeTruthy(),
+    );
+    expect(window.history.length).toBe(depth + 1);
+
+    await act(async () => {
+      const landed = new Promise((resolve) =>
+        window.addEventListener("popstate", resolve, { once: true }),
+      );
+      window.history.back();
+      await landed;
+    });
+
+    await waitFor(() =>
+      expect(logsMock).toHaveBeenLastCalledWith(
+        expect.objectContaining({
+          request_id: undefined,
+          levels: ["ERROR", "CRITICAL"],
+          q: "boom",
+        }),
+        null,
+      ),
+    );
+    expect(screen.queryByText("adminLogs.pivotRequest:req-00000001")).toBeNull();
+    const url = new URLSearchParams(window.location.search);
+    expect([url.get("lreq"), url.get("lgrp"), url.get("lq")]).toEqual([null, "error", "boom"]);
+  });
+
   it("keeps the account in use offered when the facets no longer count it", async () => {
     window.history.replaceState(null, "", "/?page=logs&lu=7");
     logsMock.mockResolvedValue({ items: [], accounts: {}, next_cursor: null });