Admit source evidence snapshots and harden stream completeness

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a06e89-93a2-7aa2-82b3-ce5ccd2682e6

src/kings_guard/posture.py

@@ -146,7 +146,9 @@ class PostureEvaluator:
             findings.append("unexpected_egress_destination")
 
         if observation.identity_binding and observation.identity_binding != "verified_token":
-            tolerance = _matching_tolerance(genome, "identity_binding", observation.identity_binding)
+            tolerance = _matching_tolerance(
+                genome, "identity_binding", observation.identity_binding
+            )
             if tolerance is None:
                 findings.append("unverified_identity_binding")
             else:
@@ -357,9 +359,8 @@ def _build_rationale(
 ) -> str:
     if posture is PostureLevel.HEALTHY:
         if tolerated_findings:
-            content = (
-                "Healthy posture with tolerated deviations only: "
-                + ", ".join(tolerated_findings)
+            content = "Healthy posture with tolerated deviations only: " + ", ".join(
+                tolerated_findings
             )
         else:
             content = "Healthy posture: observation is compatible with declared intent."
@@ -375,10 +376,7 @@ def _build_rationale(
     if completeness is StreamCompleteness.COMPLETE:
         stream_text = "Stream completeness is complete."
     elif completeness is StreamCompleteness.DEGRADED:
-        stream_text = (
-            "This judgment rests on a stream I cannot vouch for "
-            f"({completeness_reason})."
-        )
+        stream_text = f"This judgment rests on a stream I cannot vouch for ({completeness_reason})."
     else:
         stream_text = (
             "Stream completeness is unknown; confidence scores the record, "