acl: hardening suite (+25) — diamonds, cycles, validation, audit save/restore

New adversarial/cross-phase coverage: diamond resource+group hierarchies
(deny wins per path), chain inheritance + leaf deny, cycle termination,
multi-peer delegation, fact validation, audit snapshot/restore round-trip.
Adds acl-validate-facts/acl-facts-valid? (schema) and acl-audit-snapshot/
restore!/copy (audit). Fixed acl-audit-restore! rebuilding the live log via
map (append! silently no-ops on map-derived lists).

Suite is prover-free: a substrate JIT bug loops the recursive proof
reconstructor on deep chains in warm processes (documented in Blockers);
acl-permit? is unaffected. 145/145.

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

lib/acl/schema.sx

@@ -50,3 +50,22 @@
         (and
           (has-key? acl-edb-arity pred)
           (= (- (len f) 1) (get acl-edb-arity pred)))))))
+
+;; Return the sublist of facts that fail acl-fact-valid?. Empty list means the
+;; whole set is well-formed. acl-build-db stays lenient (Datalog accepts any
+;; tuple, and custom action symbols are allowed); callers opt in to checking.
+(define
+  acl-validate-facts
+  (fn
+    (facts)
+    (let
+      ((bad (list)))
+      (do
+        (for-each
+          (fn (f) (when (not (acl-fact-valid? f)) (append! bad f)))
+          facts)
+        bad))))
+
+(define
+  acl-facts-valid?
+  (fn (facts) (= (len (acl-validate-facts facts)) 0)))