Implement various scenarios as page routes in tasks-3.0 and tasks-2.0 apps

We can use routing to define different test case scenarios as pages and reuse the same app setup and common code. Currently, the apps are simple, creating and removing tasks and fetching them through a single method or subscription.

Real-world scenarios will involve more subscriptions, methods, nested reactivity, and additional logic. In future iterations, we can use the same apps with different routes to test more complex scenarios. New Playwright scripts can target these routes while reusing the existing scripts and setup.

Start by comparing the tasks-3.0 and tasks-2.0 apps and their existing app setup, common code, and Playwright scripts. Identify how routes can represent separate task scenarios while reusing the current setup. Done means both apps expose the planned scenario pages and new Playwright scripts can target those routes without duplicating the shared setup.

Written by the indexing model from the issue text.