The ws/wss transport carries a raw byte stream (yamux), but the
golang.org/x/net/websocket Conn defaults to text frames (PayloadType
TextFrame). Per RFC 6455 §5.6 a text frame must contain valid UTF-8, so
RFC-compliant intermediaries (API gateways / reverse proxies) validate
the payload and close the connection when the binary tunnel data is not
valid UTF-8.
This goes unnoticed peer-to-peer because x/net/websocket does not
validate UTF-8 on read, but it breaks the connection through a compliant
validating proxy. Set PayloadType to BinaryFrame on both the server
listener and the client dialer so the tunnel is framed as binary.
- pkg/util/net/websocket.go: store ln parameter in struct to prevent
nil pointer panic when Addr() is called
- pkg/auth/oidc.go: replace unsynchronized []string with map + RWMutex
for subjectsFromLogin to fix data race across concurrent connections
