Reuse SSH for WebCRT SFTP and fix folder navigation UX.

Open SFTP on the live session transport after SSH connect, pass the target path on every list refresh, and use folder/file icons in the browser panel.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_webcrt.py

@@ -734,6 +734,28 @@ class WebcrtServiceTests(unittest.TestCase):
         # Direct SSH is allowed (no raise).
         _require_ssh_direct({"protocol": "ssh", "hop_enabled": False}, {"protocol": "ssh"})
 
+    @patch.object(svc, "_audit")
+    def test_find_ssh_session_for_ne_prefers_attached(self, _mock_audit: MagicMock) -> None:
+        conn = _FakeConn()
+        sess = svc.WebcrtSession(
+            session_id="sftpne",
+            ne_id="ne-sftp",
+            ne_name="lab",
+            ne_ip="1.2.3.4",
+            protocol="ssh",
+            cols=80,
+            rows=24,
+            conn=conn,  # type: ignore[arg-type]
+        )
+        sess.state = "ready"
+        sess.attached = True
+        with svc._sessions_lock:
+            svc._sessions["sftpne"] = sess
+        found = svc.find_ssh_session_for_ne("ne-sftp")
+        self.assertIs(found, sess)
+        self.assertIsNone(svc.find_ssh_session_for_ne("other"))
+        svc.close_session("sftpne", reason="test")
+
     @patch.object(svc, "_audit")
     def test_reattach_clears_detach_deadline(self, _mock_audit: MagicMock) -> None:
         conn = _FakeConn()