fix: map native uuid column types to string

[felipesauer]

Fixes #107

Problem

UUID columns are generated as unknown instead of string. Since Laravel 11 the column type comes from the database schema instead of Doctrine DBAL, so $table->uuid() is reported as:

Driver	Column type	Before	After
PostgreSQL	uuid	unknown	string
MariaDB 10.7+	uuid	unknown	string
SQL Server	uniqueidentifier	unknown	string
MySQL	char(36)	string	string
SQLite	varchar	string	string

The existing guid entry (#52) is the Doctrine DBAL name, which Laravel no longer reports, and uuid was not part of the Laravel 11 mappings added after #71.

Solution

Add uuid and uniqueidentifier to the native column type mappings, next to char, varchar and the other types from #71.

Tests

The test suite runs on SQLite, where uuid columns already map to string, so the new test calls MapReturnType directly with the real mappings from GetMappings. It fails before the change (unknown) and passes after it. Locally on PHP 8.4: 131 tests passing, pint --test and phpstan clean.