Add protocol-certification M0 catalog, loader, and empty report (2.64.0).

Versioned JSON skeletons without invented ohms/mm/ps. RECOMMENDED is not
FAIL-mandatory; typical-as-standard is rejected. Report Protocolli is empty
until recognition (M1+). Native src overlays inherited periscopex on the
package path.

tests/conftest.py

@@ -16,8 +16,11 @@ for p in (
     REPO_ROOT,
 ):
     s = str(p)
-    if p.is_dir() and s not in sys.path:
-        sys.path.insert(0, s)
+    if not p.is_dir():
+        continue
+    if s in sys.path:
+        sys.path.remove(s)
+    sys.path.insert(0, s)
 
 from backend.vendor_path import ensure_impedancefinder