Harden scrubber: redact private IPs (allow-listed, not rejected)

app.py

@@ -126,7 +126,7 @@ async def donate(request: Request):
     # The skill should have already removed everything. If the backstop still
     # finds high-confidence secrets, refuse: something slipped through.
     secret_kinds = {k: v for k, v in report["redactions"].items()
-                    if k not in ("home_path", "email")}
+                    if k not in ("home_path", "email", "private_ip")}
     if secret_kinds:
         return JSONResponse(
             {