[WSLC] [BLOCKED ON WSLCSDK] State-aware daemon should expose native STDIO handles

[jsidewhite]

Description of the task

Via WslcGetProcessIOHandle (https://wsl.dev/api-reference/c/process-apis/wslcgetprocessiohandle/)

&

typedef enum WslcProcessIOHandle
{
    WSLC_PROCESS_IO_HANDLE_STDIN = 0,
    WSLC_PROCESS_IO_HANDLE_STDOUT = 1,
    WSLC_PROCESS_IO_HANDLE_STDERR = 2
} WslcProcessIOHandle;

https://wsl.dev/api-reference/c/enumerations/wslcprocessiohandle/

Additional context

No response

[SohamDas2021]

I was already tracking this in ADO and this is blocked on WSLC SDK. Context below:

WslcGetProcessIOHandle(WSLC_PROCESS_IO_HANDLE_STDIN) returns E_INVALIDARG. CreateRelayedProcessIO creates and relays a stdin pipe, but only when WSLCProcessFlagsStdin is set (otherwise it closes stdin outright), and wslc exec -i sets it, which is why the CLI has working stdin and we don't.

The gap looks confined to the SDK layer: CopyProcessSettingsToRuntime leaves WSLCProcessOptions::Flags unset under a // TODO: No user access, and WslcProcessSettings exposes no setter for it, so no SDK caller can reach stdin.

Reached out to WSLC SDK team- microsoft/WSL#41695

[SohamDas2021]

Tracked in ADO