Add DashboardFilterBar and move global filters to top of dashboard

- Create DashboardFilterBar component with time-range and origin-filter
  toggle-button groups in a single card row (Stage 7, Tasks 7.1–7.3)
- Integrate filter bar below ServerStatusBar in DashboardPage; remove
  filter toolbars from the Ban List section header (Task 7.2)
- Add 6 tests covering rendering, active-state reflection, and callbacks
- tsc --noEmit, eslint, npm run build, npm test all pass (27/27 tests)

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

@@ -0,0 +1,128 @@
+/**
+ * Tests for the DashboardFilterBar component.
+ *
+ * Covers rendering, active-state reflection, and callback invocation.
+ */
+
+import { describe, it, expect, vi } from "vitest";
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { FluentProvider, webLightTheme } from "@fluentui/react-components";
+import { DashboardFilterBar } from "../DashboardFilterBar";
+import type { BanOriginFilter, TimeRange } from "../../types/ban";
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+interface RenderProps {
+  timeRange?: TimeRange;
+  onTimeRangeChange?: (value: TimeRange) => void;
+  originFilter?: BanOriginFilter;
+  onOriginFilterChange?: (value: BanOriginFilter) => void;
+}
+
+function renderBar({
+  timeRange = "24h",
+  onTimeRangeChange = vi.fn<(value: TimeRange) => void>(),
+  originFilter = "all",
+  onOriginFilterChange = vi.fn<(value: BanOriginFilter) => void>(),
+}: RenderProps = {}): {
+  onTimeRangeChange: (value: TimeRange) => void;
+  onOriginFilterChange: (value: BanOriginFilter) => void;
+} {
+  render(
+    <FluentProvider theme={webLightTheme}>
+      <DashboardFilterBar
+        timeRange={timeRange}
+        onTimeRangeChange={onTimeRangeChange}
+        originFilter={originFilter}
+        onOriginFilterChange={onOriginFilterChange}
+      />
+    </FluentProvider>,
+  );
+  return { onTimeRangeChange, onOriginFilterChange };
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+describe("DashboardFilterBar", () => {
+  // -------------------------------------------------------------------------
+  // 1. Renders all time-range buttons
+  // -------------------------------------------------------------------------
+  it("renders all four time-range buttons", () => {
+    renderBar();
+    expect(screen.getByRole("button", { name: /last 24 h/i })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /last 7 days/i })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /last 30 days/i })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /last 365 days/i })).toBeInTheDocument();
+  });
+
+  // -------------------------------------------------------------------------
+  // 2. Renders all origin-filter buttons
+  // -------------------------------------------------------------------------
+  it("renders all three origin-filter buttons", () => {
+    renderBar();
+    expect(screen.getByRole("button", { name: /^all$/i })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /blocklist/i })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /selfblock/i })).toBeInTheDocument();
+  });
+
+  // -------------------------------------------------------------------------
+  // 3. Active state matches props
+  // -------------------------------------------------------------------------
+  it("marks the correct time-range button as active", () => {
+    renderBar({ timeRange: "7d" });
+    expect(
+      screen.getByRole("button", { name: /last 7 days/i }),
+    ).toHaveAttribute("aria-pressed", "true");
+    expect(
+      screen.getByRole("button", { name: /last 24 h/i }),
+    ).toHaveAttribute("aria-pressed", "false");
+  });
+
+  it("marks the correct origin-filter button as active", () => {
+    renderBar({ originFilter: "blocklist" });
+    expect(
+      screen.getByRole("button", { name: /blocklist/i }),
+    ).toHaveAttribute("aria-pressed", "true");
+    expect(
+      screen.getByRole("button", { name: /^all$/i }),
+    ).toHaveAttribute("aria-pressed", "false");
+  });
+
+  // -------------------------------------------------------------------------
+  // 4. Time-range click fires callback
+  // -------------------------------------------------------------------------
+  it("calls onTimeRangeChange with the correct value when a time-range button is clicked", async () => {
+    const user = userEvent.setup();
+    const { onTimeRangeChange } = renderBar({ timeRange: "24h" });
+    await user.click(screen.getByRole("button", { name: /last 30 days/i }));
+    expect(onTimeRangeChange).toHaveBeenCalledOnce();
+    expect(onTimeRangeChange).toHaveBeenCalledWith("30d");
+  });
+
+  // -------------------------------------------------------------------------
+  // 5. Origin-filter click fires callback
+  // -------------------------------------------------------------------------
+  it("calls onOriginFilterChange with the correct value when an origin button is clicked", async () => {
+    const user = userEvent.setup();
+    const { onOriginFilterChange } = renderBar({ originFilter: "all" });
+    await user.click(screen.getByRole("button", { name: /selfblock/i }));
+    expect(onOriginFilterChange).toHaveBeenCalledOnce();
+    expect(onOriginFilterChange).toHaveBeenCalledWith("selfblock");
+  });
+
+  // -------------------------------------------------------------------------
+  // 6. Already-active button click still fires callback
+  // -------------------------------------------------------------------------
+  it("calls onTimeRangeChange even when the active button is clicked again", async () => {
+    const user = userEvent.setup();
+    const { onTimeRangeChange } = renderBar({ timeRange: "24h" });
+    await user.click(screen.getByRole("button", { name: /last 24 h/i }));
+    expect(onTimeRangeChange).toHaveBeenCalledOnce();
+    expect(onTimeRangeChange).toHaveBeenCalledWith("24h");
+  });
+});