Create end-to-end testing suite for framework integrations (React, Solid, etc.)

We should create a comprehensive end-to-end testing suite for all LiveStore framework integrations, such as React and Solid. The goal is to ensure that all framework integrations are tested in a consistent and rigorous manner.

The test suite should include:

• End-to-end tests for each supported framework integration (e.g., React, Solid, etc.)
• Tests for running an app with multiple LiveStore instances simultaneously
• Tests covering various app life cycles, such as shutting down the app, reloading code, and other relevant scenarios

This will help ensure reliability and consistency across all supported frameworks and catch integration-specific issues early.

Framework integrations

• React (built-in)
• Solid (built-in)
• https://github.com/livestorejs/livestore/issues/313
• https://github.com/slashv/vue-livestore