feat: enhance Playwright testing setup with E2E tests, new skills, and improved documentation

- Added E2E test setup in `auth_api.py` with `/e2e-seed` endpoint for database reset and test user creation.
- Integrated Playwright for end-to-end testing in the frontend with necessary dependencies in `package.json` and `package-lock.json`.
- Created Playwright configuration in `playwright.config.ts` to manage test execution and server setup.
- Developed new skills for Playwright best practices, visual regression, smoke test generation, and self-healing tests.
- Implemented new test cases for chore creation in `chores-create.smoke.spec.ts` and `chores-create.spec.ts`.
- Added page object models for `ChildEditPage` and `LandingPage` to streamline test interactions.
- Updated `.gitignore` to exclude Playwright reports and test results.
- Enhanced documentation in `copilot-instructions.md` for testing and E2E setup.

.github/skills/playwright-smoke-gen/SKILL.md

@@ -0,0 +1,11 @@
+---
+name: playwright-smoke-gen
+description: Generates high-level smoke tests by exploring a running web application.
+---
+# Playwright Smoke Test Instructions
+When this skill is active, follow these rules:
+1. **Explore First**: Use the Playwright MCP `snapshot` tool to understand the page structure before writing code.
+2. **Web-First Assertions**: Always use `expect(locator).toBeVisible()` or `toBeEnabled()`.
+3. **Naming Convention**: Save tests in `tests/smoke/[feature].spec.ts`.
+4. **Setup/Teardown**: Use `test.beforeEach` for repeated actions like navigating to the base URL.
+5. **No Hardcoded Secrets**: If a login is required, use `process.env.TEST_USER` placeholders.