Support passing socket options (e.g. `reuseAddr`) to the underlying dgram socket

When creating an `Http3Server`, there is currently no way to pass options to the underlying `node:dgram` socket created internally by `Http3WebTransportServerSocket`. The socket is created with only the `type` field: ```js // lib/serversocket.js, init() this.socketInt = createSocket({ type: result.family === 4 ? 'udp4' : 'udp6' }) ``` Node's `dgram.createSocket()` supports additional options like `reuseAddr`, `reusePort`, `recvBufferSize`, `sendBufferSize`, and `signal` — none of which can be configured through the `Http3Server` constructor today. ## Why this matters The most impactful missing option is `reuseAddr: true` (`SO_REUSEADDR`). Without it, after a server shuts down (or is killed), the OS may not immediately release the UDP port. A new server instance trying to bind the same port can fail with `EADDRINUSE`, even though no process is actively using it. This is especially problematic in development workflows where servers are frequently restarted (e.g. via `tsx watch`, `nodemon`, or similar file-watching tools). It also affects production graceful-restart scenarios where a new instance must bind the same port before the old instance has fully terminated. On macOS in particular, the port can remain unavailable for a noticeable window after process exit when `SO_REUSEADDR` is not set. ## Proposed API Allow passing through `dgram.SocketOptions` (or a subset) via the existing `Http3Server` / `Http3WebTransportServerSocket` constructor args: ```js const server = new Http3Server({ host: '0.0.0.0', port: 3001, cert: '...', privKey: '...', // new: forward to dgram.createSocket() socketOptions: { reuseAddr: true, }, }); ``` And in `Http3WebTransportServerSocket.init()`: ```js this.socketInt = createSocket({ type: result.family === 4 ? 'udp4' : 'udp6', reuseAddr: this.args?.socketOptions?.reuseAddr ?? false, // ...other forwarded options }) ``` ## Workaround There is currently no clean workaround. The `socketInt` property is set asynchronously inside `init()` after a DNS lookup, so it cannot be intercepted and replaced from outside. The only option is patching the library source or using `patch-package`.