Fix VP bind server rejecting TLS connections on port 3002 (#559)

BambuStudio uses TLS on port 3002 for certain printer models (e.g. A1
  Mini / N1). The bind server only spoke plain TCP on both ports, so the
  TLS ClientHello was rejected as "invalid frame" and the slicer could
  never discover or connect to the virtual printer.

  Port 3002 now uses TLS (reusing the VP's existing certificate), port
  3000 remains plain TCP. Also updated proxy-mode to use TLSProxy for
  the port 3002 bind proxy instead of raw TCPProxy.

backend/tests/unit/services/test_virtual_printer.py

@@ -1405,4 +1405,6 @@ class TestBindServer:
                 model="3DPrinter-X1-Carbon",
                 name="Bambuddy",
                 bind_address="192.168.1.50",
+                cert_path=Path("/tmp/cert.pem"),  # nosec B108
+                key_path=Path("/tmp/key.pem"),  # nosec B108
             )