docs: rewrite PLAN.md and update CODEBASE.md, README.md

- Full rewrite of PLAN.md to reflect current architecture (27 REST + 3 WS endpoints,
  embedded frontend, automation, scheduler, health check, GoReleaser CI)
- Added health.go, mods.go, scheduler.go, robfig/cron dep to CODEBASE.md
- Added Gitea Actions CI/CD section to CODEBASE.md
- Added conventional commits to code style section
- Added missing API routes and embed/ to README.md

frontend/src/components/Layout.test.tsx

@@ -0,0 +1,49 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import { MemoryRouter } from 'react-router-dom'
+import Layout from './Layout'
+
+describe('Layout', () => {
+  it('renders sidebar navigation', () => {
+    render(
+      <MemoryRouter>
+        <Layout>
+          <div>Content</div>
+        </Layout>
+      </MemoryRouter>
+    )
+
+    expect(screen.getByText('Dashboard')).toBeInTheDocument()
+    expect(screen.getByText('Settings')).toBeInTheDocument()
+    expect(screen.getByText('Configs')).toBeInTheDocument()
+    expect(screen.getByText('Modlists')).toBeInTheDocument()
+    expect(screen.getByText('Mods')).toBeInTheDocument()
+    expect(screen.getByText('Logs')).toBeInTheDocument()
+    expect(screen.getByText('Status')).toBeInTheDocument()
+  })
+
+  it('renders children', () => {
+    render(
+      <MemoryRouter>
+        <Layout>
+          <div>Test Content</div>
+        </Layout>
+      </MemoryRouter>
+    )
+
+    expect(screen.getByText('Test Content')).toBeInTheDocument()
+  })
+
+  it('highlights active route', () => {
+    render(
+      <MemoryRouter initialEntries={['/settings']}>
+        <Layout>
+          <div>Content</div>
+        </Layout>
+      </MemoryRouter>
+    )
+
+    const settingsLink = screen.getByText('Settings')
+    expect(settingsLink).toHaveClass('text-white')
+  })
+})

frontend/src/pages/Mods.test.tsx

@@ -0,0 +1,79 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { render, screen, waitFor } from '@testing-library/react'
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { MemoryRouter } from 'react-router-dom'
+import Mods from './Mods'
+
+const mockList = vi.fn()
+
+vi.mock('../api/client', () => ({
+  modsApi: {
+    list: (...args: unknown[]) => mockList(...args),
+    remove: vi.fn(),
+    cleanup: vi.fn(),
+  },
+}))
+
+const createTestQueryClient = () =>
+  new QueryClient({
+    defaultOptions: {
+      queries: { retry: false },
+      mutations: { retry: false },
+    },
+  })
+
+describe('Mods', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('renders loading state then data', async () => {
+    mockList.mockResolvedValue([])
+    const queryClient = createTestQueryClient()
+    render(
+      <QueryClientProvider client={queryClient}>
+        <MemoryRouter>
+          <Mods />
+        </MemoryRouter>
+      </QueryClientProvider>
+    )
+
+    expect(screen.getByText('Loading...')).toBeInTheDocument()
+
+    await waitFor(() => {
+      expect(screen.getByText('Installed Mods')).toBeInTheDocument()
+    })
+  })
+
+  it('renders search input after load', async () => {
+    mockList.mockResolvedValue([])
+    const queryClient = createTestQueryClient()
+    render(
+      <QueryClientProvider client={queryClient}>
+        <MemoryRouter>
+          <Mods />
+        </MemoryRouter>
+      </QueryClientProvider>
+    )
+
+    await waitFor(() => {
+      expect(screen.getByPlaceholderText('Filter by name or ID...')).toBeInTheDocument()
+    })
+  })
+
+  it('shows no mods message when empty', async () => {
+    mockList.mockResolvedValue([])
+    const queryClient = createTestQueryClient()
+    render(
+      <QueryClientProvider client={queryClient}>
+        <MemoryRouter>
+          <Mods />
+        </MemoryRouter>
+      </QueryClientProvider>
+    )
+
+    await waitFor(() => {
+      expect(screen.getByText('No mods found.')).toBeInTheDocument()
+    })
+  })
+})

frontend/src/test/setup.ts

@@ -0,0 +1 @@
+import '@testing-library/jest-dom'

frontend/src/utils/format.test.ts

@@ -0,0 +1,35 @@
+import { describe, it, expect } from 'vitest'
+import { fmtSize } from './format'
+
+describe('fmtSize', () => {
+  it('formats 0 bytes', () => {
+    expect(fmtSize(0)).toBe('0 B')
+  })
+
+  it('formats bytes', () => {
+    expect(fmtSize(500)).toBe('500 B')
+  })
+
+  it('formats kilobytes', () => {
+    expect(fmtSize(1024)).toBe('1.0 KB')
+    expect(fmtSize(1536)).toBe('1.5 KB')
+  })
+
+  it('formats megabytes', () => {
+    expect(fmtSize(1048576)).toBe('1.0 MB')
+    expect(fmtSize(5242880)).toBe('5.0 MB')
+  })
+
+  it('formats gigabytes', () => {
+    expect(fmtSize(1073741824)).toBe('1.0 GB')
+  })
+
+  it('formats terabytes', () => {
+    expect(fmtSize(1099511627776)).toBe('1.0 TB')
+  })
+
+  it('handles edge case at 1024 boundary', () => {
+    expect(fmtSize(1023)).toBe('1023 B')
+    expect(fmtSize(1025)).toBe('1.0 KB')
+  })
+})

frontend/src/utils/format.ts

@@ -0,0 +1,7 @@
+export function fmtSize(bytes: number): string {
+  if (bytes === 0) return '0 B'
+  const units = ['B', 'KB', 'MB', 'GB', 'TB']
+  const i = Math.min(Math.floor(Math.log(bytes) / Math.log(1024)), units.length - 1)
+  const v = bytes / Math.pow(1024, i)
+  return `${v.toFixed(i > 0 ? 1 : 0)} ${units[i]}`
+}