fix: support native Windows control transport

[kimjunny]

Summary

• add native Windows named-pipe control transport while preserving Unix domain sockets
• secure Windows IPC with owner-only ACLs, random authenticated endpoints, bounded frames/connections, and per-session lifetime locks
• use native APPDATA/LOCALAPPDATA defaults and add Windows CI coverage
• keep the optional Herdr plugin scoped to Linux and macOS

Validation

• cargo fmt --check
• cargo check --all-targets
• cargo test (696 unit, 15 architecture, 9 CLI)
• cargo clippy --all-targets --all-features -- -D warnings
• slophammer-rs dry . --format json
• slophammer-rs check . --format json
• npx -y @simpledoc/simpledoc check
• cargo package --locked
• targeted cargo-mutants run: no missed mutants; timeout-only exit 3 accepted by scripts/ci-local.sh
• native Windows install and manual QA: help, invalid input, offline rendering, live sessions/open/set, duplicate bind rejection, endpoint and process cleanup