mod: Phase 4 — federation (trust, sharing, revocation), 132/132 — roadmap done

Cross-instance reports ingest into the local registry with origin tags; the
engine decides them unchanged. Decision sharing pushes to a mock fed-sx outbox
(mod/fed-send! is the transport seam). Trust is advisory by default: a peer's
decision binds locally only under (mod/trusted? peer :mod), else it lands in the
advisory log unapplied. Revocation composes with the Phase-2 proof model —
fed-revoke-if-invalidated re-runs the engine and undoes moderation only when the
action no longer holds (exoneration flips hide→keep → revoked + origin notified).
+26 fed tests. Full mod-on-sx roadmap complete.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/mod/scoreboard.json

@@ -1,12 +1,13 @@
 {
   "lang": "mod",
-  "total_passed": 106,
+  "total_passed": 132,
   "total_failed": 0,
-  "total": 106,
+  "total": 132,
   "suites": [
     {"name":"decide","passed":31,"failed":0,"total":31},
     {"name":"audit","passed":29,"failed":0,"total":29},
-    {"name":"escalation","passed":46,"failed":0,"total":46}
+    {"name":"escalation","passed":46,"failed":0,"total":46},
+    {"name":"fed","passed":26,"failed":0,"total":26}
   ],
-  "generated": "2026-06-06T17:49:32+00:00"
+  "generated": "2026-06-06T17:54:02+00:00"
 }