Use host-managed SSH accounts for browser terminal

scripts/service_manager.sh

@@ -29,11 +29,6 @@ ensure_transformerlab_default_user() {
 }
 
 check_wetty_prereqs() {
-  if ! id "$COURSEWARE_STUDENT_USERNAME" >/dev/null 2>&1; then
-    echo "Missing terminal user '$COURSEWARE_STUDENT_USERNAME'. Re-run ./labctl up after setting COURSEWARE_STUDENT_PASSWORD_HASH." >&2
-    exit 1
-  fi
-
   if [ ! -x "$WETTY_BIN" ]; then
     echo "Missing WeTTY binary at $WETTY_BIN. Re-run ./labctl up." >&2
     exit 1
@@ -44,11 +39,6 @@ check_wetty_prereqs() {
     exit 1
   fi
 
-  if [ ! -d "$COURSEWARE_LAB3_DIR" ]; then
-    echo "Missing lab workspace at $COURSEWARE_LAB3_DIR. Re-run ./labctl up." >&2
-    exit 1
-  fi
-
   if ! python3 - <<'PY'
 import socket, sys
 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)