Resolve CodeQL ineffectual-statement findings in protocol method stubs

[Copilot]

This PR addresses the three requested code-quality findings (#5, #6, #7) by removing ineffectual expression statements in protocol method bodies. The update is limited to the flagged locations and preserves typing/protocol intent.

• Scope

  • Updated only:
    • bowtie/_commands.py
    • bowtie/_core.py

• Changes

  • Replaced ... expression statements in protocol method bodies with pass:
    • Command.to_request(...)
    • Command.from_response(...)
    • _MakeValidator.__call__(...)

• Why this resolves the findings

  • ... as a bare expression is reported as py/ineffectual-statement; pass provides an explicit no-op body for protocol stubs without changing interface contracts.

class Command(Protocol[R]):
    def to_request(self, validate: Callable[..., None]) -> dict[str, Any]:
        pass

    @staticmethod
    def from_response(response: bytes, validate: Callable[..., None]) -> R | None:
        pass