v3.32.4: rebuild the link on card insertion (the first attempt)

v3.32.2 fixed the endless re-arm, but on Windows the first attempt
still failed on the old link (seen in the confirmation log: the
"self._con.connect()" traceback) and only the retry recovered - a failed
init, a 2-4 s delay and a traceback in the log.

The monitor's insert path now marks the transport stale under
_CARD_LOCK, so the first equip attempt rebuilds the PC/SC link.  It also
covers a link created at a cardless startup (never connected).  The
rebuild still happens in the equip worker, never in the pyscard monitor
thread, and _ensure_transport releases the old link first.

Docs: the READMEs' troubleshooting bullet.
Tests: an insertion marks the transport for the rebuild.
1014 Python + 953 frontend green; simple-v462.

tests/test_card_monitor.py

@@ -35,8 +35,11 @@ class TestCardPresenceObserver(unittest.TestCase):
         self.trigger_mock = self.trigger.start()
         self.saved_auto = S._AUTO_EQUIP
         S._AUTO_EQUIP = True
+        self.saved_stale = S._TRANSPORT_STALE
+        S._TRANSPORT_STALE = False
 
     def tearDown(self):
+        S._TRANSPORT_STALE = self.saved_stale
         S._AUTO_EQUIP = self.saved_auto
         self.trigger.stop()
         self.patcher.stop()
@@ -61,6 +64,16 @@ class TestCardPresenceObserver(unittest.TestCase):
         self.assertEqual(self.disconnects, [])
         self.trigger_mock.assert_called_once()
 
+    def test_insertion_marks_the_transport_for_a_rebuild(self):
+        # The first equip attempt must already use a fresh link: after a swap
+        # the old one cannot connect on Windows, and a cardless-startup link
+        # never connected (v3.32.4).
+        S._TRANSPORT_STALE = False
+        self.server.card_present = False
+        self.observer.update(None, ([FakeCard('Test Reader 00 00')], []))
+        self.assertTrue(S._TRANSPORT_STALE)
+        self.trigger_mock.assert_called_once()
+
     def test_insertion_does_not_trigger_when_disabled(self):
         S._AUTO_EQUIP = False
         self.server.card_present = False