…t imports

Removes in-memory active client tracking (`$activeClients` array and
associated event listeners) from `LaravelHttpTransport`. This local tracking
was unreliable due to Laravel's typical request-response lifecycle where
the transport instance is re-initialized per interaction.

The `ClientStateManager`, which uses a persistent cache, is already
responsible for managing active client state and activity across requests.
The `LaravelHttpTransport` now correctly relies solely on `ClientStateManager`
for queuing messages (`sendToClientAsync`) and updates client activity
via `ClientStateManager` when messages are received.

- Bump `php-mcp/server` to version `^2.3`
- Refactor `McpNotificationListener` to utilize the `Registry` for handling notifications, removing reliance on `ClientStateManager`.
- Clean up unused methods and improve event handling logic in `McpServiceProvider` and `McpNotificationListener`.

When starting the tool is VSCode without providing a transport, it can't "Choose transport protocol for MCP server communication", so we need to explicitly define it.