Add PHPDoc annotations to stubs for better PHPStan support (#738)

[chetanupare]

What stubs were updated

• Model generation output (PHPDoc-enabled mode):
  • Models generated when blueprint.generate_phpdocs=true now include a trait-level PHPDoc @use annotation for HasFactory.
• No stub template file was changed (e.g. stubs/model.class.stub stayed the same).
  • The change is implemented in the generator: src/Generators/ModelGenerator.php (overrides trait rendering for models).
• Test fixtures updated to reflect the new expected output:
  • tests/fixtures/models/readme-example-phpdoc.php
  • tests/fixtures/models/relationships-phpdoc.php
  • tests/fixtures/models/soft-deletes-phpdoc.php
  • tests/fixtures/models/disable-auto-columns-phpdoc.php
  • tests/fixtures/models/foreign-key-shorthand-phpdoc.php

Example before / after

Before (generated model, PHPDoc enabled):

class Post extends Model
{
    use HasFactory;
}

After (generated model, PHPDoc enabled):

class Post extends Model
{
    /** @use HasFactory<\Database\Factories\PostFactory> */
    use HasFactory;
}

SoftDeletes stays a real trait (no regression):

class Comment extends Model
{
    /** @use HasFactory<\Database\Factories\CommentFactory> */
    use HasFactory, SoftDeletes;
}

How this improves static analysis (PHPStan / IDE type inference)

• Eliminates missing/unclear generic warnings for HasFactory by explicitly declaring the factory type via @use HasFactory<...>.
• Improves IDE autocomplete and navigation:
  • IDEs can more reliably infer the associated Factory class for a model and offer better completion for factory-related calls.
• Keeps runtime behavior unchanged:
  • This is purely an annotation enhancement; traits like SoftDeletes remain actual use SoftDeletes; statements (not moved into PHPDoc).