Linter and quality tools

## Description

Install and configure tools and practices to improve code quality.

### Quality and Development Tools

* **Set up CodeRabbit** — Configure automated AI-powered code reviews and integrate them into the pull request workflow.
* **Set up Biome** — Configure formatting, linting, and code-quality rules across the project.
* **Freeze Dependencies** — Lock dependency versions to ensure consistent and reproducible builds.
* **Set up PostHog** — Integrate product analytics and user behavior tracking.
* **Set up Sentry** — Integrate error tracking, performance monitoring, and application observability.

Start by inspecting the project's dependency and development configuration, then determine how the pull request workflow supports CodeRabbit and how Biome, PostHog, and Sentry should be integrated. Done means the requested tools are configured, dependency versions are locked, and each integration is usable in the project workflow.

Written by the indexing model from the issue text.