feat(status): report web and attach endpoints

[whackur]

Summary

• report the web viewer's actual runtime HTTP endpoint in nightcrow status
• rename the local transport field to Attach endpoint so it is not mistaken for a TCP port
• provide an actionable restart error when an updated CLI reaches the legacy status wire shape
• cover IPv6 URL formatting, protocol validation, rendering, and read-only status behavior

Verification

• cargo fmt --all --check
• cargo build --locked --workspace
• cargo test --locked --workspace
• cargo clippy --locked --workspace --all-targets --all-features -- -D warnings
• docker compose run --rm unix-gate