acl: Phase 1 direct grants + deny-overrides, 24 tests

Datalog ACL layer (schema/facts/engine/api) over lib/datalog/. Direct
grant permits unless explicit deny names same (S,A,R) — deny-overrides
via stratified negation. Conformance wrapper + scoreboard.

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

lib/acl/conformance.conf

@@ -0,0 +1,25 @@
+# ACL conformance config — sourced by lib/guest/conformance.sh.
+
+LANG_NAME=acl
+MODE=dict
+
+PRELOADS=(
+  lib/datalog/tokenizer.sx
+  lib/datalog/parser.sx
+  lib/datalog/unify.sx
+  lib/datalog/db.sx
+  lib/datalog/builtins.sx
+  lib/datalog/aggregates.sx
+  lib/datalog/strata.sx
+  lib/datalog/eval.sx
+  lib/datalog/api.sx
+  lib/datalog/magic.sx
+  lib/acl/schema.sx
+  lib/acl/facts.sx
+  lib/acl/engine.sx
+  lib/acl/api.sx
+)
+
+SUITES=(
+  "direct:lib/acl/tests/direct.sx:(acl-direct-tests-run!)"
+)