Attach optional Railiance recording-time evidence

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a09cbb-87c6-7900-a145-4ce53ba9f1a6

src/warden/clock_attribution.py

@@ -0,0 +1,17 @@
+"""Optional recording-time evidence; original local timestamps remain intact."""
+import os
+
+def recording_time():
+    if not os.environ.get('WARDEN_CLOCK_TRUST_FILE'):
+        return {}
+    try:
+        from railiance_clock.attribution import from_environment
+        result = from_environment('WARDEN_CLOCK_TRUST_FILE')
+        # These are time observations, not raw credentials. Keep audit metadata
+        # within the existing detector's restrictions without weakening it.
+        if result.get('railiance_time', {}).get('status') == 'usable':
+            result['railiance_time'].pop('epoch', None)
+            result['railiance_time'].pop('sample_id', None)
+        return result
+    except (ImportError, OSError, ValueError):
+        return {'railiance_time': {'status': 'unavailable', 'kind': 'recording_time'}}