feat(logging-p0): add screenshot capture and browser console diagnostics for ERP errors

Enhance ERP automation error diagnostics by capturing PNG screenshots
on every error and forwarding browser console warnings/errors to the
structured logger. Includes automatic cleanup of old screenshots
aligned with the configured log retention period.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/unit/services/erp/erp-error-context.test.ts

@@ -0,0 +1,133 @@
+/**
+ * Tests for ERP Error Context Capture with screenshot support
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+import fs from 'fs'
+import path from 'path'
+
+// Mock logger/shared before importing the module under test
+vi.mock('../../../../src/main/services/logger/shared', () => ({
+  getLogDir: vi.fn(() => '/tmp/test-logs')
+}))
+
+// Mock fs
+vi.mock('fs', () => ({
+  default: {
+    mkdirSync: vi.fn(),
+    writeFileSync: vi.fn(),
+    existsSync: vi.fn(() => true),
+    readdirSync: vi.fn(() => []),
+    statSync: vi.fn()
+  }
+}))
+
+import { capturePageContext } from '../../../../src/main/services/erp/erp-error-context'
+
+function createMockPage(overrides: Record<string, unknown> = {}) {
+  return {
+    url: vi.fn(() => 'https://erp.example.com/page'),
+    frames: vi.fn(() => [
+      { name: () => 'main', url: () => 'https://erp.example.com/main' },
+      { name: () => 'forwardFrame', url: () => 'https://erp.example.com/frame' }
+    ]),
+    isClosed: vi.fn(() => false),
+    screenshot: vi.fn(() => Buffer.from('fake-png-data')),
+    ...overrides
+  } as any
+}
+
+describe('capturePageContext', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    vi.mocked(fs.mkdirSync).mockReturnValue(undefined)
+    vi.mocked(fs.writeFileSync).mockReturnValue(undefined)
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('should capture screenshot and return screenshotPath on success', async () => {
+    const page = createMockPage()
+
+    const ctx = await capturePageContext(page, '#selector', 'login.username')
+
+    expect(ctx.screenshotPath).toBeDefined()
+    expect(ctx.screenshotPath).toContain('err_')
+    expect(ctx.screenshotPath).toContain('.png')
+    expect(ctx.screenshotPath).toContain('login_username')
+    expect(fs.writeFileSync).toHaveBeenCalledWith(
+      expect.stringContaining('.png'),
+      expect.any(Buffer)
+    )
+  })
+
+  it('should return screenshotPath undefined when page is closed', async () => {
+    const page = createMockPage({ isClosed: vi.fn(() => true) })
+
+    const ctx = await capturePageContext(page)
+
+    expect(ctx.screenshotPath).toBeUndefined()
+    expect(fs.writeFileSync).not.toHaveBeenCalled()
+  })
+
+  it('should still return other fields when screenshot fails', async () => {
+    const page = createMockPage({
+      screenshot: vi.fn(() => {
+        throw new Error('screenshot timeout')
+      })
+    })
+
+    const ctx = await capturePageContext(page, '#target', 'test-step')
+
+    // Other fields should still be populated
+    expect(ctx.pageUrl).toBe('https://erp.example.com/page')
+    expect(ctx.frameHierarchy).toHaveLength(2)
+    expect(ctx.targetSelector).toBe('#target')
+    expect(ctx.step).toBe('test-step')
+    // Screenshot should be undefined due to failure
+    expect(ctx.screenshotPath).toBeUndefined()
+  })
+
+  it('should sanitize special characters in step name for filename', async () => {
+    const page = createMockPage()
+
+    const ctx = await capturePageContext(page, undefined, 'login/user:test*step')
+
+    expect(ctx.screenshotPath).toBeDefined()
+    expect(ctx.screenshotPath).toContain('login_user_test_step')
+  })
+
+  it('should use "unknown" in filename when step is not provided', async () => {
+    const page = createMockPage()
+
+    const ctx = await capturePageContext(page)
+
+    expect(ctx.screenshotPath).toBeDefined()
+    expect(ctx.screenshotPath).toContain('unknown')
+  })
+
+  it('should truncate long step names to 40 characters', async () => {
+    const page = createMockPage()
+    const longStep = 'a'.repeat(80)
+
+    const ctx = await capturePageContext(page, undefined, longStep)
+
+    expect(ctx.screenshotPath).toBeDefined()
+    const filename = path.basename(ctx.screenshotPath!)
+    // Extract step portion: err_YYYYMMDD_HHmmss_<step>.png
+    const stepPart = filename.replace(/^err_\d{8}_\d{6}_/, '').replace(/\.png$/, '')
+    expect(stepPart.length).toBe(40)
+  })
+
+  it('should create screenshots directory if it does not exist', async () => {
+    const page = createMockPage()
+
+    await capturePageContext(page)
+
+    expect(fs.mkdirSync).toHaveBeenCalledWith(expect.stringContaining('screenshots'), {
+      recursive: true
+    })
+  })
+})