1.1.70

feat(SIKNet): Introduce WebSocket support and a Netty plugin framework

This commit introduces two major features to the SIKNet module: comprehensive support for WebSocket clients and servers using Netty, and a new plugin system for extending Netty managers.

### 1. WebSocket Client and Server Implementation (Netty)
This addition provides the tools to build high-performance, real-time communication applications.

*   **WebSocket Server**:
    *   `WebSocketServerConfig`: A new configuration class to set up a WebSocket server, defining port, path, and heartbeat intervals.
    *   `WebSocketServerHandler`: Manages the server-side WebSocket lifecycle, handling text/binary frames, ping/pong, close frames, and idle timeouts to automatically close inactive connections.
    *   The pipeline is configured with `HttpServerCodec`, `HttpObjectAggregator`, and `WebSocketServerProtocolHandler` for standard WebSocket handshakes and frame aggregation.

*   **WebSocket Client**:
    *   `WebSocketClientConfig`: A new configuration class that takes a WebSocket URL (`ws://` or `wss://`) and manages connection parameters like reconnect intervals.
    *   `WebSocketClientHandler`: Manages client-side logic, including sending pings on writer idle to keep the connection alive.
    *   `MessageListener`: A new interface (`onMessage`, `onRawMessage`) is introduced, allowing consumers to receive incoming text and binary data from the client.

### 2. Netty Plugin System
A new "side-channel" plugin framework has been added to allow for observing Netty events without modifying business logic or data streams.

*   **`NettyPlugin` Interface**: Defines the core contract for plugins with hooks for manager startup/shutdown (`onStarted`, `onStopping`) and channel installation (`install`).
*   **`SimplePlugin` Abstract Class**: A convenience class that simplifies plugin creation by providing simple, overridable hooks for connection events (`onConnect`, `onDisconnect`), idle events, read/write operations (`beforeRead`, `afterRead`, `beforeWrite`, `afterWrite`), and exceptions.
*   **Integration**: `NettyConfig` now accepts a list of plugins, which are automatically installed and managed by `NettyClientManager` and `NettyServerManager`.

### Refinements & Fixes

*   **`HttpExtension.kt`**:
    *   The `toMap()` extension function has been improved to safely handle `null` property values, converting them to an empty string instead of causing a crash.
    *   URL parameter construction now uses `StringBuilder` for minor style and performance improvements.
*   **`ConnectionManager.kt`**: Removed the `@JvmStatic` annotation from the singleton instance.

### Version Update

*   The project version in `gradle.properties` has been incremented from `1.1.68` to `1.1.69`.