Allow forcing socket type via driver configuration

[p123-stack]

Add Explicit Socket Type Configuration

Overview

This PR enables users to explicitly choose between Socket and Stream connection factories via driver configuration, while maintaining full backwards compatibility with auto-detection as the default behavior.

Problem

Previously, the connection factory type was determined solely by automatic detection via extension_loaded('sockets') at the singleton level. Users had no way to override this behavior, even if they wanted to force a specific connection type for performance, debugging, or compatibility reasons.

Solution

Added a new optional socketType configuration parameter that allows users to explicitly specify which connection factory to use:

• 'sockets' - Force SocketConnectionFactory (faster, requires PHP sockets extension)
• 'stream' - Force StreamConnectionFactory (always available, slightly slower)
• null (default) - Auto-detect based on available extensions (existing behavior)

Changes

1. DriverConfiguration - Added socketType property with getter/setter methods
2. SystemWideConnectionFactory - Updated getInstance() to accept preferred socket type parameter
3. BoltFactory - Updated create() to pass socket type to SystemWideConnectionFactory
4. ConnectionPool - Updated create() to extract and pass socket type from configuration
5. Tests - Added comprehensive unit tests covering all socket type scenarios

Usage Example

// Force Stream factory
$config = DriverConfiguration::default()->withSocketType('stream');
$driver = BoltDriver::create('neo4j://localhost', $config);

// Force Socket factory
$config = DriverConfiguration::default()->withSocketType('sockets');
$driver = BoltDriver::create('neo4j://localhost', $config);

// Auto-detect (default)
$config = DriverConfiguration::default();
$driver = BoltDriver::create('neo4j://localhost', $config);### Implementation Details

• Config-first approach: Driver configuration takes precedence over auto-detection
• Non-breaking: All new parameters are optional; existing code continues to work unchanged
• Minimal footprint: ~40 lines of implementation code across 4 files
• No refactoring: Only additive changes, no architectural modifications

Testing

New test coverage:

• Socket type override to Stream
• Socket type override to Socket (when extension available)
• Configuration stores socket type correctly
• BoltFactory accepts socket type parameter

Backwards Compatibility

Fully backwards compatible - all new parameters default to null which preserves existing auto-detection behavior.

[transistive]

Great work! We just need a few small changes to get it out the door

[transistive]

I would throw an error if a socket is provided, but no socket extension is loaded. Maybe a DriverConfigurationError with a short message like: Cannot enforce socket extension usage if the extension is not enabled.

[transistive]

Let's use an enum instead of a string for better type safety and built-in documentation