relations: Phase 4 federation (erel trust-gating, peer_rel/trust, fed-sx mock transport, revocation) + 22 tests

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

lib/relations/api.sx

@@ -1,47 +1,16 @@
-;; lib/relations/api.sx — relationship lifecycle + queries over lib/datalog/.
+;; lib/relations/api.sx — relationship lifecycle + current-db convenience layer.
 ;;
-;; A relations db is a live Datalog db holding rel(Src,Dst,Kind) facts under the
-;; engine ruleset (lib/relations/engine.sx). Direct children/parents are plain
-;; queries on the rel relation; transitive reachability/roots/leaves/cycles come
-;; from the engine's recursive rules.
-;;
-;; Two surfaces: db-threading core fns (relations-children-of db ...) and a
-;; current-db convenience layer (relations/relate ...) for callers that load a
-;; fact base once and query without passing the db around. This mirrors lib/acl.
+;; A relations db is a live Datalog db holding rel(Src,Dst,Kind) facts (and, for
+;; federation, peer_rel/trust facts) under the engine ruleset
+;; (lib/relations/engine.sx). The query functions live in engine.sx; this module
+;; owns db construction, the assert/retract lifecycle, and a current-db
+;; convenience layer for callers that load a fact base once and query without
+;; threading the db around. This mirrors lib/acl/api.sx.
 
 (define
   relations-build-db
   (fn (facts) (dl-program-data facts relations-rules)))
 
-;; Direct children: every Dst with rel(node, Dst, kind).
-(define
-  relations-children-of
-  (fn
-    (db node kind)
-    (relations-pluck
-      (dl-query db (list (quote rel) node (quote Dst) kind))
-      :Dst)))
-
-;; Direct parents: every Src with rel(Src, node, kind).
-(define
-  relations-parents-of
-  (fn
-    (db node kind)
-    (relations-pluck
-      (dl-query db (list (quote rel) (quote Src) node kind))
-      :Src)))
-
-;; Directly related: neighbours in either direction under kind.
-(define
-  relations-related
-  (fn
-    (db node kind)
-    (append
-      (relations-children-of db node kind)
-      (relations-parents-of db node kind))))
-
-;; --- current-db convenience layer ---
-
 (define relations-current-db nil)
 
 (define