Add support for setting table connection name

[dereuromark]

Summary

• Add setConnection(string $connectionName) method to BaseFactory and EventCollector to allow factories to use a different database connection
• This enables testing scenarios where entities need to be persisted to specific connections
• Replace unset($this->table) with $this->table = null for consistency (as suggested in review)

Changes

• Add connectionName property to EventCollector
• Add setConnection() method to EventCollector and BaseFactory with fluent interface
• Update getTable() to use custom connection when specified via ConnectionManager::get()
• Add test_dummy connection config in bootstrap for testing
• Add tests for setConnection functionality

Usage

// Set a custom connection for the factory
ArticleFactory::make()
    ->setConnection('other_database')
    ->persist();

// Works with chaining
ArticleFactory::make()
    ->setConnection('other_database')
    ->listeningToBehaviors('Sluggable')
    ->persist();

Test plan

• Added tests for setConnection() method
• Added tests for method chaining with setConnection()
• All 437 existing tests pass
• PHPStan passes
• Code style passes

Based on PR #257 with review feedback addressed (using = null instead of unset()).

🤖 Generated with Claude Code

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[dereuromark]

Oops, my bad: dereuromark#11