test: fix broken unit tests, add missing fixtures, and stabilize CI pipeline

- Fix os module mock pattern for Vitest v4 in proxy-ide-config tests

- Fix enterprise oauth_client_key expectations in cloudHandler-sync and token-manager-parity tests

- Fix proxy-controller integration test argument expectations

- Add missing proxy-parity JSON fixtures (OpenAI tools, Anthropic tool-use, Gemini SSE)

- Add reasoning_content mapping to convertClaudeToOpenAIResponse

- Fix google-api service test env var cache leak with resetModules + dynamic imports

- Fix proxy-metrics timer tests by calling onModuleInit in beforeEach

- Fix locale-sensitive number formatting in StatCard tests

- Add missing test files to version control (components, hooks, ipc, mocks, server, utils)

- Fix CI workflows: testing.yaml (use vitest run, add type-check job, npm cache), lint.yaml and format.yaml (add npm cache, concurrency, fix job names)

src/tests/unit/components/usage/StatCard.test.tsx

@@ -0,0 +1,125 @@
+import React from 'react';
+import { screen } from '@testing-library/react';
+import { renderWithProviders } from '@/tests/unit/test-utils';
+import { StatCard } from '@/components/usage/StatCard';
+import { Activity, TrendingUp, Users, Zap } from 'lucide-react';
+import { vi, beforeAll, afterAll } from 'vitest';
+
+describe('StatCard', () => {
+  beforeAll(() => {
+    vi.spyOn(Number.prototype, 'toLocaleString').mockImplementation(function (this: number) {
+      return this.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
+    });
+  });
+
+  afterAll(() => {
+    vi.restoreAllMocks();
+  });
+  it('renders label and value', () => {
+    renderWithProviders(
+      <StatCard label="Total Tokens" value={12345} icon={Activity} />,
+    );
+    expect(screen.getByText('Total Tokens')).toBeInTheDocument();
+    expect(screen.getByText('12,345')).toBeInTheDocument();
+  });
+
+  it('renders string values correctly', () => {
+    renderWithProviders(
+      <StatCard label="Status" value="Active" icon={Zap} />,
+    );
+    expect(screen.getByText('Active')).toBeInTheDocument();
+  });
+
+  it('formats number values with locale string', () => {
+    renderWithProviders(
+      <StatCard label="Requests" value={1000000} icon={TrendingUp} />,
+    );
+    expect(screen.getByText('1,000,000')).toBeInTheDocument();
+  });
+
+  it('shows skeleton when isLoading is true', () => {
+    renderWithProviders(
+      <StatCard label="Loading" value={0} icon={Users} isLoading />,
+    );
+    expect(screen.queryByText('0')).not.toBeInTheDocument();
+    expect(document.querySelector('.animate-pulse')).toBeInTheDocument();
+  });
+
+  it('does not show skeleton when isLoading is false', () => {
+    renderWithProviders(
+      <StatCard label="Loaded" value={42} icon={Activity} isLoading={false} />,
+    );
+    expect(screen.getByText('42')).toBeInTheDocument();
+    expect(document.querySelector('.animate-pulse')).not.toBeInTheDocument();
+  });
+
+  it('renders icon element', () => {
+    renderWithProviders(
+      <StatCard label="With Icon" value={100} icon={Zap} />,
+    );
+    expect(document.querySelector('svg')).toBeInTheDocument();
+  });
+
+  it('applies custom className', () => {
+    renderWithProviders(
+      <StatCard label="Styled" value={1} icon={Activity} className="my-stat" />,
+    );
+    expect(screen.getByText('Styled').closest('[class*="border-border"]')).toHaveClass('my-stat');
+  });
+
+  it('applies default slate accent when accent prop is not provided', () => {
+    const { container } = renderWithProviders(
+      <StatCard label="Default Accent" value={1} icon={Activity} />,
+    );
+    const iconContainer = container.querySelector('.rounded-md');
+    expect(iconContainer).toHaveClass('bg-slate-500/5');
+  });
+
+  it('applies blue accent', () => {
+    const { container } = renderWithProviders(
+      <StatCard label="Blue" value={1} icon={Activity} accent="blue" />,
+    );
+    const iconContainer = container.querySelector('.rounded-md');
+    expect(iconContainer).toHaveClass('bg-blue-500/5');
+  });
+
+  it('applies green accent', () => {
+    const { container } = renderWithProviders(
+      <StatCard label="Green" value={1} icon={Activity} accent="green" />,
+    );
+    const iconContainer = container.querySelector('.rounded-md');
+    expect(iconContainer).toHaveClass('bg-emerald-500/5');
+  });
+
+  it('applies amber accent', () => {
+    const { container } = renderWithProviders(
+      <StatCard label="Amber" value={1} icon={Activity} accent="amber" />,
+    );
+    const iconContainer = container.querySelector('.rounded-md');
+    expect(iconContainer).toHaveClass('bg-amber-500/5');
+  });
+
+  it('applies purple accent', () => {
+    const { container } = renderWithProviders(
+      <StatCard label="Purple" value={1} icon={Activity} accent="purple" />,
+    );
+    const iconContainer = container.querySelector('.rounded-md');
+    expect(iconContainer).toHaveClass('bg-purple-500/5');
+  });
+
+  it('has uppercase label styling', () => {
+    renderWithProviders(
+      <StatCard label="Uppercase Test" value={1} icon={Activity} />,
+    );
+    const label = screen.getByText('Uppercase Test');
+    expect(label).toHaveClass('uppercase');
+  });
+
+  it('has mono font for value', () => {
+    renderWithProviders(
+      <StatCard label="Mono" value={999} icon={Activity} />,
+    );
+    const value = screen.getByText('999');
+    expect(value).toHaveClass('font-mono');
+  });
+});