feat(mobile): FilterChips + AgentCard WCAG 2.1 AA accessibility

FilterChips:
- Add role=toolbar + aria-label="Filter agents" on container
- Add role=radio + aria-checked on each button
- Add aria-hidden on count spans
- FilterChips.test.tsx: 9 cases

AgentCard:
- Add aria-label composing name, status, tier, remote flag
- AgentCard.test.tsx: 8 cases

🤖 Generated with [Claude Code](https://claude.com/claude-code)

canvas/src/components/mobile/__tests__/AgentCard.test.tsx

@@ -0,0 +1,115 @@
+// @vitest-environment jsdom
+/**
+ * AgentCard — mobile agent row card.
+ *
+ * Per WCAG 2.1 AA:
+ *   - Rendered as <button> with aria-label composing accessible name
+ *   - aria-label includes: name, status, tier, remote flag
+ *
+ * NOTE: No @testing-library/jest-dom — use DOM APIs.
+ */
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, render } from "@testing-library/react";
+import React from "react";
+
+import { AgentCard, type MobileAgent } from "../components";
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+  vi.resetModules();
+});
+
+const onlineAgent: MobileAgent = {
+  id: "ws-1",
+  name: "My Agent",
+  tag: "claude-code",
+  tier: "T2",
+  status: "online",
+  remote: false,
+  runtime: "claude-code",
+  skills: 3,
+  calls: 12,
+  desc: "Handles customer support",
+  parentId: null,
+};
+
+const remoteFailedAgent: MobileAgent = {
+  id: "ws-2",
+  name: "Remote Worker",
+  tag: "external",
+  tier: "T4",
+  status: "failed",
+  remote: true,
+  runtime: "external",
+  skills: 5,
+  calls: 0,
+  desc: "",
+  parentId: "ws-1",
+};
+
+// ─── Render ───────────────────────────────────────────────────────────────────
+
+describe("AgentCard — render", () => {
+  it("renders as a button", () => {
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={vi.fn()} />);
+    expect(document.querySelector("button")).toBeTruthy();
+  });
+
+  it("button has aria-label with name, status, tier", () => {
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={vi.fn()} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    const label = btn.getAttribute("aria-label") ?? "";
+    expect(label).toContain("My Agent");
+    expect(label).toContain("online");
+    expect(label).toContain("T2");
+  });
+
+  it("aria-label includes remote for remote agents", () => {
+    render(<AgentCard agent={remoteFailedAgent} dark={false} onClick={vi.fn()} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    const label = btn.getAttribute("aria-label") ?? "";
+    expect(label).toContain("Remote Worker");
+    expect(label).toContain("failed");
+    expect(label).toContain("T4");
+    expect(label).toContain("remote");
+  });
+
+  it("aria-label omits remote for non-remote agents", () => {
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={vi.fn()} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    const label = btn.getAttribute("aria-label") ?? "";
+    expect(label).not.toContain("remote");
+  });
+
+  it("renders agent name text inside the button", () => {
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={vi.fn()} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    expect(btn.textContent).toContain("My Agent");
+  });
+
+  it("compact prop reduces padding", () => {
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={vi.fn()} compact={true} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    const style = btn.getAttribute("style") ?? "";
+    // compact uses "12px 14px" padding vs "14px 16px" default
+    expect(style).toContain("padding");
+  });
+});
+
+// ─── Interaction ─────────────────────────────────────────────────────────────
+
+describe("AgentCard — interaction", () => {
+  it("calls onClick when button is clicked", () => {
+    const onClick = vi.fn();
+    render(<AgentCard agent={onlineAgent} dark={false} onClick={onClick} />);
+    const btn = document.querySelector("button") as HTMLButtonElement;
+    btn.click();
+    expect(onClick).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders without onClick (optional prop)", () => {
+    // Should not throw
+    expect(() => render(<AgentCard agent={onlineAgent} dark={false} />)).not.toThrow();
+  });
+});

canvas/src/components/mobile/__tests__/FilterChips.test.tsx

@@ -0,0 +1,118 @@
+// @vitest-environment jsdom
+/**
+ * FilterChips — mobile agent filter toolbar.
+ *
+ * Per WCAG 2.1 AA / ARIA radio group pattern:
+ *   - Container has role="toolbar" + aria-label
+ *   - Each button has role="radio" + aria-checked
+ *   - Icon spans have aria-hidden="true"
+ *   - Only one radio can be checked at a time (single-select filter)
+ *
+ * NOTE: No @testing-library/jest-dom — use DOM APIs.
+ */
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { cleanup, fireEvent, render } from "@testing-library/react";
+import React from "react";
+
+import { FilterChips, type AgentFilter } from "../components";
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+  vi.resetModules();
+});
+
+const defaultCounts = { all: 12, online: 8, issue: 2, paused: 2 };
+
+// ─── Render ───────────────────────────────────────────────────────────────────
+
+describe("FilterChips — render", () => {
+  it("renders 4 filter buttons", () => {
+    render(<FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const buttons = document.querySelectorAll('[role="radio"]');
+    expect(buttons.length).toBe(4);
+  });
+
+  it("container has role=toolbar and aria-label", () => {
+    render(<FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const toolbar = document.querySelector('[role="toolbar"]');
+    expect(toolbar).toBeTruthy();
+    expect(toolbar?.getAttribute("aria-label")).toBe("Filter agents");
+  });
+
+  it("each button has role=radio", () => {
+    render(<FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const buttons = document.querySelectorAll('[role="radio"]');
+    buttons.forEach((btn) => {
+      expect(btn.getAttribute("role")).toBe("radio");
+    });
+  });
+
+  it("active filter has aria-checked=true, others false", () => {
+    render(<FilterChips value="issue" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const buttons = document.querySelectorAll('[role="radio"]');
+    buttons.forEach((btn) => {
+      const label = btn.textContent ?? "";
+      if (label.startsWith("Issues")) {
+        expect(btn.getAttribute("aria-checked")).toBe("true");
+      } else {
+        expect(btn.getAttribute("aria-checked")).toBe("false");
+      }
+    });
+  });
+
+  it("count spans have aria-hidden=true", () => {
+    render(<FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const hidden = document.querySelectorAll('[aria-hidden="true"]');
+    // Each chip has one count span marked aria-hidden
+    expect(hidden.length).toBeGreaterThanOrEqual(4);
+  });
+});
+
+// ─── Interaction ─────────────────────────────────────────────────────────────
+
+describe("FilterChips — interaction", () => {
+  it("calls onChange with correct filter id when clicked", () => {
+    const onChange = vi.fn();
+    render(<FilterChips value="all" onChange={onChange} dark={false} counts={defaultCounts} />);
+    const buttons = document.querySelectorAll('[role="radio"]');
+    const onlineBtn = Array.from(buttons).find((b) => b.textContent?.startsWith("Online")) as Element;
+    fireEvent.click(onlineBtn);
+    expect(onChange).toHaveBeenCalledWith("online");
+  });
+
+  it("calls onChange when the already-active filter is clicked (component does not guard)", () => {
+    const onChange = vi.fn();
+    render(<FilterChips value="all" onChange={onChange} dark={false} counts={defaultCounts} />);
+    const buttons = document.querySelectorAll('[role="radio"]');
+    const allBtn = Array.from(buttons).find((b) => b.textContent?.startsWith("All")) as Element;
+    fireEvent.click(allBtn);
+    // Component calls onChange even for the already-active filter;
+    // the guard belongs at the consumer level (MobileHome) if needed.
+    expect(onChange).toHaveBeenCalledWith("all");
+  });
+
+  it("updating value prop changes aria-checked", () => {
+    const { rerender } = render(
+      <FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />,
+    );
+    const allBtn = document.querySelector('[id="filter-all"]') as Element;
+    expect(allBtn.getAttribute("aria-checked")).toBe("true");
+
+    rerender(<FilterChips value="paused" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    expect(allBtn.getAttribute("aria-checked")).toBe("false");
+    const pausedBtn = document.querySelector('[id="filter-paused"]') as Element;
+    expect(pausedBtn.getAttribute("aria-checked")).toBe("true");
+  });
+
+  it("all filter labels are present", () => {
+    render(<FilterChips value="all" onChange={vi.fn()} dark={false} counts={defaultCounts} />);
+    const texts = Array.from(document.querySelectorAll('[role="radio"]')).map((b) =>
+      b.textContent?.trim(),
+    );
+    expect(texts.some((t) => t?.startsWith("All"))).toBe(true);
+    expect(texts.some((t) => t?.startsWith("Online"))).toBe(true);
+    expect(texts.some((t) => t?.startsWith("Issues"))).toBe(true);
+    expect(texts.some((t) => t?.startsWith("Paused"))).toBe(true);
+  });
+});

canvas/src/components/mobile/components.tsx

@@ -287,6 +287,7 @@ export function AgentCard({
   return (
     <button
       type="button"
+      aria-label={`${agent.name}, status: ${agent.status}, tier ${agent.tier}${agent.remote ? ", remote" : ""}`}
       onClick={onClick}
       style={{
         display: "block",
@@ -420,6 +421,9 @@ export function FilterChips({
   ];
   return (
     <div
+      role="toolbar"
+      aria-label="Filter agents"
+      aria-activedescendant={value ? `filter-${value}` : undefined}
       style={{
         display: "flex",
         gap: 6,
@@ -433,7 +437,10 @@ export function FilterChips({
         return (
           <button
             key={o.id}
+            id={`filter-${o.id}`}
+            role="radio"
             type="button"
+            aria-checked={on}
             onClick={() => onChange(o.id)}
             style={{
               display: "inline-flex",
@@ -453,6 +460,7 @@ export function FilterChips({
           >
             {o.label}
             <span
+              aria-hidden="true"
               style={{
                 fontSize: 10.5,
                 opacity: 0.7,