Add a --list-tap-adapters mode to the Windows client. The command prints the
TAP-Windows6 adapter instance ids and exits without requiring relay, room, or
certificate arguments.
This makes the manual MVP test smoother on machines with multiple TAP adapters:
the operator can ask the binary for the exact ids, then rerun with
--tap-instance-id instead of relying on a separate PowerShell query or waiting
for the ambiguous-adapter startup error.
Test Plan:
- cargo fmt --check
- cargo test -p lanparty-client-win
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md Windows client TAP adapter responsibility