Enforce explicit responsibility attribution

- document responsibility attribution as a project-wide invariant
- prevent inferred ownership in protocol rendering
- add negative gold regression for false responsibility assignment
- document future responsibility evidence and attribution model
- record the real-life benchmark finding

docs/pipeline.md

@@ -10,6 +10,22 @@ The guiding principle is simple:
 
 > **Each processing stage has exactly one responsibility.**
 
+Cross-cutting invariant:
+
+> **Responsibility attribution requires explicit evidence.**
+
+A person, team or department may be recorded as responsible only when the
+source material explicitly assigns, accepts or confirms that responsibility.
+The pipeline must not infer ownership from thematic proximity, discussion
+participation, mentioning a task, commenting on another department,
+organizational assumptions, likely job roles, speaker adjacency or model world
+knowledge.
+
+When support is incomplete or ambiguous, leave the responsible person unset,
+mark the item as unclear where supported, and preserve the attribution
+evidence. This applies to extraction, canonicalization, semantic consolidation,
+Canonical Meeting Knowledge and every Output View renderer.
+
 ---
 
 # Pipeline Overview