Add dynamic pricing E2E test suite with Playwright

Implement comprehensive E2E tests to validate the surge pricing pipeline:
- Test SimpleSurgePricer with configurable thresholds (high=3, surge=1.5x)
- Verify discount pricing when demand is below low_threshold
- Test multi-product differential pricing based on demand signals
- Validate price propagation from pipeline through Redis to API

Test infrastructure:
- Playwright configuration with custom fixtures
- Python pipeline worker for direct test execution (bypasses Airflow)
- API client for event ingestion and price verification
- Event generator for creating realistic interaction sequences
- docker-compose.e2e.yml with minimal services for testing

e2e/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "phantom-e2e-tests",
+  "version": "1.0.0",
+  "description": "E2E tests for PHANTOM Dynamic Pricing Pipeline",
+  "scripts": {
+    "test": "playwright test",
+    "test:ui": "playwright test --ui",
+    "test:headed": "playwright test --headed",
+    "test:debug": "playwright test --debug",
+    "test:report": "playwright show-report",
+    "test:pricing": "playwright test dynamic-pricing",
+    "test:health": "playwright test --grep 'health'",
+    "pipeline:run": "python3 lib/pipeline-worker.py --store-mode hotel --high-threshold 3 --surge-multiplier 1.5",
+    "pipeline:dry-run": "python3 lib/pipeline-worker.py --dry-run --json-output",
+    "services:check": "curl -s http://localhost:5000/health && curl -s http://localhost:5001/health"
+  },
+  "devDependencies": {
+    "@playwright/test": "^1.49.0",
+    "@types/node": "^20.0.0",
+    "typescript": "^5.0.0",
+    "uuid": "^9.0.0",
+    "@types/uuid": "^9.0.0"
+  },
+  "engines": {
+    "node": ">=18.0.0"
+  }
+}