parked relay: a supervisor that keeps it alive + a REMOTE restart the operator can actually reach

Completes the travelling-operator deployment.  The relay stays parked on the
home machine (so no player ever edits join.bat) and the console dials in from
anywhere -- but until now two things needed hands on that machine: bringing the
relay back when it died, and restarting it (the only way to clear a wedge or
pick up a roster resize).  Both are covered now.

tools/btrelay_park.py -- the supervisor:
  * runs the relay with cwd=content\ , which is what pins WHICH
    operator_secret.txt is live (the trap documented last commit);
  * relaunches on ANY exit, with 2/5/15/30/60s backoff when a relay dies inside
    20s, so a permanent fault (port taken, missing egg) cannot become a spin;
  * rotates content\parked_relay.log to .1 first, so the dead generation's
    evidence survives the relaunch that replaces it;
  * Ctrl-C stops it for good.  NOT a Windows service on purpose: session 0
    would hide the window an operator wants to tail.
tools/park_relay.cmd -- double-click to park; a shortcut to it in shell:startup
  gives start-after-reboot with no admin rights.

`restart` on the control port (btconsole.py): sets restart_requested, the run
loop returns, relay_main exits RESTART_EXIT_CODE=42 and the supervisor relaunches
-- re-reading the egg.  REFUSED while a mission is running (launches_sent >= 2
and not stop_sent): bouncing then would drop every pod out of a live round.
Local stdin gets the same command for parity.

btoperator.py: Restart Session in REMOTE mode now sends `restart` and reconnects
6s later instead of just tearing down our own link -- the old behaviour looked
like "Restart does nothing" against a parked relay.  (QTimer had to be imported;
it was missing, which py_compile does not catch -- it would have been a runtime
NameError on the first click.)

VERIFIED by scratchpad/test_parked_supervisor.py, 12/12, and the full
test_remote_console_e2e.py re-run green afterwards (15/15):
  * kill the relay -> a NEW pid is serving again, and the old log is kept as .1;
  * remote `restart` -> ACKed, new pid, egg re-read, serving again;
  * the supervisor distinguishes the two -- "operator requested a restart" vs
    the crash/backoff path -- proven from its own log, not assumed;
  * the mid-mission guard is present and wired to launches_sent/stop_sent.

Two harness defects fixed while proving it, both mine: a check written with
`or True` that could never fail (replaced with two real assertions against the
supervisor's log), and a recv that treated the relay's correct
close-after-restart as a ConnectionResetError failure.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/btoperator.py

@@ -24,7 +24,8 @@ import socket
 import sys
 import threading
 
-from PySide6.QtCore import Qt, QProcess, QProcessEnvironment, QThread, Signal
+from PySide6.QtCore import (Qt, QProcess, QProcessEnvironment, QThread, QTimer,
+                            Signal)
 from PySide6.QtGui import QColor, QFont, QPalette, QAction
 from PySide6.QtWidgets import (
     QApplication, QCheckBox, QComboBox, QFileDialog, QFormLayout, QGroupBox,
@@ -966,6 +967,21 @@ class Operator(QMainWindow):
     def _restart_session(self):
         """Next round: same mission/roster, fresh session.  Players just
         re-run their join script."""
+        if getattr(self, "remote_link", None):
+            # PARKED RELAY: we do not own that process, so tearing down our
+            # own link would only disconnect us (the old behaviour, which
+            # looked like "Restart did nothing").  Ask the relay itself to
+            # restart -- its supervisor relaunches it, re-reading the egg, so
+            # a roster resize or a wedge is recoverable from the road.  Then
+            # reconnect once it is back up.
+            host = self.f_relayhost.text().strip()
+            self.log.appendPlainText(
+                "== asking the parked relay at %s to RESTART "
+                "(reconnecting in a few seconds) ==" % host)
+            self._relay_send("restart")
+            self._stop_session()
+            QTimer.singleShot(6000, self._start_session)
+            return
         self.log.appendPlainText("== restarting session ==")
         self._stop_session()
         self._start_session()