fix(auth): authenticate producer-signed decisions before authorization

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a140c4-354a-7823-8f0d-8f717397f786

scripts/check_pdp_producer_source.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+"""Verify exact vendored producer bytes and optionally a prospective upstream.
+
+Updates require reviewed replacement of API/sign files, fixture refresh from the
+producer, and reviewed manifest hashes/revision; this checker never updates them.
+"""
+import argparse
+import hashlib
+import json
+from pathlib import Path
+
+parser=argparse.ArgumentParser()
+parser.add_argument('--upstream',type=Path)
+args=parser.parse_args()
+root=Path(__file__).resolve().parents[1]
+manifest=json.loads((root/'verifier/producer-source.json').read_text())
+for name,digest in manifest['files'].items():
+    assert hashlib.sha256((root/'verifier'/name).read_bytes()).hexdigest()==digest, name
+    if args.upstream:
+        assert hashlib.sha256((args.upstream/name).read_bytes()).hexdigest()==digest, 'upstream drift: '+name
+for name,digest in manifest['fixtures'].items():
+    assert hashlib.sha256((root/'tests/fixtures/pdp-signature'/name).read_bytes()).hexdigest()==digest, name
+print('producer source and fixture hashes match the admitted source snapshot')