[Bug]: Terminal resize SIGWINCH forwarding prints missing signal in xpc message

## Description

When running a long-lived foreground command with `container run`, terminal resize events can produce repeated XPC signal forwarding errors on stderr:

```text
failed to send signal: ["error": invalidArgument: "missing signal in xpc message", "signal": 28]
```

Signal 28 is `SIGWINCH`. The workload continues compiling, so this appears to be a CLI/terminal resize forwarding issue rather than an application failure, but it pollutes stderr during long-running builds and makes it harder to detect real build errors.

## Environment

```text
container CLI version 1.0.0 (build: release, commit: unspeci)
macOS 26.5.1 (25F80)
Darwin 25.5.0 arm64
Host hardware: Apple Silicon
Shell: zsh
```

`container system status` reports the apiserver running:

```text
status running
apiserver.version container-apiserver version 1.0.0 (build: release, commit: unspeci)
```

## Observed output

This happened while running a Rust build in a foreground Apple container session. The build was still making progress, then stderr repeatedly printed:

```text
Compiling tokio v1.52.3
Compiling futures-macro v0.3.32
Compiling futures-task v0.3.32
Compiling serde_json v1.0.149
Compiling futures-util v0.3.32
Compiling pkg-config v0.3.32
failed to send signal: ["error": invalidArgument: "missing signal in xpc message", "signal": 28]
failed to send signal: ["error": invalidArgument: "missing signal in xpc message", "signal": 28]
failed to send signal: ["error": invalidArgument: "missing signal in xpc message", "signal": 28]
failed to send signal: ["error": invalidArgument: "missing signal in xpc message", "signal": 28]
```

## Expected behavior

Terminal resize events should either:

- be forwarded successfully as `SIGWINCH`, or
- be ignored without printing an internal XPC error to stderr.

The CLI should not emit repeated internal `missing signal in xpc message` errors during normal terminal resize handling.

## Notes

A direct signal send did not reproduce the same error:

```shell
CID="$(container run --detach quay.io/libpod/alpine:latest sleep 300)"
container kill --signal WINCH "$CID"
container kill "$CID"
```

That suggests the issue is likely specific to the foreground CLI's terminal resize/signal forwarding path rather than generic signal delivery.

Start with the foreground `container run` CLI entry point and reproduce the issue by resizing the terminal during a long-running command. Compare that path with the direct `container kill --signal WINCH` check described in the issue; done means resize events are forwarded successfully or ignored without repeated `missing signal in xpc message` errors.

Written by the indexing model from the issue text.