fixes: https://github.com/coder/internal/issues/1143
Both gVisor and the Go standard library implementations of `net.Conn` can under certain circumstances return `nil` for `RemoteAddr()` and `LocalAddr()` calls. If we call their methods, we segfault.
This PR fixes these calls and adds ruleguard rules.
Note that `slog.F("remote_addr", conn.RemoteAddr())` is fine because slog detects the `nil` before attempting to stringify the type.
Spike Curtis
40df21ed62