[13.x] Add foreignUuidFor schema helper

[Tresor-Kasenda]

This PR adds a foreignUuidFor helper to schema blueprints.

While foreignIdFor already supports UUID-backed Eloquent models by detecting the model key type, this new helper provides an explicit API for migrations that intentionally want a UUID foreign key column:

$table->foreignUuidFor(User::class)->constrained();

The helper mirrors the model-aware behavior of foreignIdFor by inferring:

• the foreign key column name from the model
• the related table name
• the referenced primary key column