Debugging database errors with Insights

Introduces a new error tracking feature to PlanetScale Insights, allowing users to view and debug database errors. Details an internal use case where the feature was used to identify and resolve `AlreadyExists` errors caused by a race condition in the `database_branch_password` table. Explains how the error tracking, combined with application-level debugging and understanding of uniqueness constraints, led to the identification of the root cause and a solution. Also enhances tag searching functionality for queries and errors in Insights.