Add protocol-certification M9 L3 channel certifier (2.71.0).

L3 CHANNEL structure for timing budget, insertion loss, return loss,
crosstalk, and complete channel. Numeric PASS/FAIL only from existing
channel FACT; otherwise a visible skip. No OpenEMS, no invented S-parameters,
no M6 packs.

tests/pcb/test_protocol_report_m5.py

@@ -95,8 +95,8 @@ def test_result_rank_fail_before_warning():
 
 def test_usb2_pair_l0_pass_l2_z_unknown_no_invented_ohm():
     sec, _ = protocol_exam(_usb_connected())
-    assert sec.max_level_reached == "L2"
-    assert sec.macrophase == "M8"
+    assert sec.max_level_reached == "L3"
+    assert sec.macrophase == "M9"
     usb = next(
         r for r in sec.recognized_instances
         if "usb" in str(r.get("logical_protocol_id"))