feat: implement v0.4.0 - Reports, Charts, Comparison, Dark Mode, E2E Testing

Backend (@backend-dev):
- Add ReportService with PDF/CSV generation (reportlab, pandas)
- Implement Report API endpoints (POST, GET, DELETE, download)
- Add ReportRepository and schemas
- Configure storage with auto-cleanup (30 days)
- Rate limiting: 10 downloads/minute
- Professional PDF templates with charts support

Frontend (@frontend-dev):
- Integrate Recharts for data visualization
- Add CostBreakdown, TimeSeries, ComparisonBar charts
- Implement scenario comparison page with multi-select
- Add dark/light mode toggle with ThemeProvider
- Create Reports page with generation form and list
- Add new UI components: checkbox, dialog, tabs, label, skeleton
- Implement useComparison and useReports hooks

QA (@qa-engineer):
- Setup Playwright E2E testing framework
- Create 7 test spec files with 94 test cases
- Add visual regression testing with baselines
- Configure multi-browser testing (Chrome, Firefox, WebKit)
- Add mobile responsive tests
- Create test fixtures and helpers
- Setup GitHub Actions CI workflow

Documentation (@spec-architect):
- Create detailed kanban-v0.4.0.md with 27 tasks
- Update progress.md with v0.4.0 tracking
- Create v0.4.0 planning prompt

Features:
✅ PDF/CSV Report Generation
✅ Interactive Charts (Pie, Area, Bar)
✅ Scenario Comparison (2-4 scenarios)
✅ Dark/Light Mode Toggle
✅ E2E Test Suite (94 tests)

Dependencies added:
- Backend: reportlab, pandas, slowapi
- Frontend: recharts, date-fns, @radix-ui/react-checkbox/dialog/tabs
- Testing: @playwright/test

27 tasks completed, 100% v0.4.0 implementation

frontend/e2e/fixtures/test-logs.ts

@@ -0,0 +1,117 @@
+/**
+ * Test Logs Fixtures
+ * 
+ * Sample log data for E2E testing
+ */
+
+export interface TestLog {
+  timestamp: string;
+  level: 'INFO' | 'WARN' | 'ERROR' | 'DEBUG';
+  message: string;
+  service: string;
+  metadata?: Record<string, unknown>;
+}
+
+export const testLogs: TestLog[] = [
+  {
+    timestamp: new Date().toISOString(),
+    level: 'INFO',
+    message: 'Application started successfully',
+    service: 'lambda',
+    metadata: {
+      functionName: 'test-function',
+      memorySize: 512,
+      duration: 1250,
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 1000).toISOString(),
+    level: 'INFO',
+    message: 'Processing SQS message batch',
+    service: 'sqs',
+    metadata: {
+      queueName: 'test-queue',
+      batchSize: 10,
+      messageCount: 5,
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 2000).toISOString(),
+    level: 'INFO',
+    message: 'Bedrock LLM invocation completed',
+    service: 'bedrock',
+    metadata: {
+      modelId: 'anthropic.claude-3-sonnet-20240229-v1:0',
+      inputTokens: 150,
+      outputTokens: 250,
+      duration: 2345,
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 3000).toISOString(),
+    level: 'WARN',
+    message: 'Potential PII detected in request',
+    service: 'lambda',
+    metadata: {
+      piiType: 'EMAIL',
+      confidence: 0.95,
+      masked: true,
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 4000).toISOString(),
+    level: 'ERROR',
+    message: 'Failed to process message after 3 retries',
+    service: 'sqs',
+    metadata: {
+      errorCode: 'ProcessingFailed',
+      retryCount: 3,
+      deadLetterQueue: true,
+    },
+  },
+];
+
+export const logsWithPII: TestLog[] = [
+  {
+    timestamp: new Date().toISOString(),
+    level: 'INFO',
+    message: 'User login: john.doe@example.com',
+    service: 'lambda',
+    metadata: {
+      userId: 'user-12345',
+      email: 'john.doe@example.com',
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 1000).toISOString(),
+    level: 'INFO',
+    message: 'Payment processed for card ending 4532',
+    service: 'lambda',
+    metadata: {
+      cardLastFour: '4532',
+      amount: 99.99,
+      currency: 'USD',
+    },
+  },
+  {
+    timestamp: new Date(Date.now() - 2000).toISOString(),
+    level: 'INFO',
+    message: 'Phone verification: +1-555-123-4567',
+    service: 'lambda',
+    metadata: {
+      phone: '+1-555-123-4567',
+      verified: true,
+    },
+  },
+];
+
+export const highVolumeLogs: TestLog[] = Array.from({ length: 100 }, (_, i) => ({
+  timestamp: new Date(Date.now() - i * 100).toISOString(),
+  level: i % 10 === 0 ? 'ERROR' : i % 5 === 0 ? 'WARN' : 'INFO',
+  message: `Log entry ${i + 1}: ${i % 3 === 0 ? 'SQS message processed' : i % 3 === 1 ? 'Lambda invoked' : 'Bedrock API call'}`,
+  service: i % 3 === 0 ? 'sqs' : i % 3 === 1 ? 'lambda' : 'bedrock',
+  metadata: {
+    sequenceNumber: i + 1,
+    batchId: `batch-${Math.floor(i / 10)}`,
+  },
+}));