datalog: dl-query accepts conjunctive goal lists (167/167)

dl-query now auto-dispatches on the first element's shape:
- positive literal (head is a symbol) or {:neg ...} dict → wrap
- list of literals → conjunctive query

dl-query-coerce normalizes; dl-query-user-vars collects the union
of user-named vars (deduped, '_' filtered) for projection. Old
single-literal callers unchanged.

  (dl-query db '(p X))                   ; single
  (dl-query db '((p X) (q X)))           ; conjunction
  (dl-query db (list '(n X) '(> X 2)))   ; with comparison

2 new api tests cover multi-goal AND and conjunction with comparison.

plans/datalog-on-sx.md

@@ -222,7 +222,11 @@ large graphs.
       ```
 - [x] `(dl-rule head body)` constructor for the dict form.
 - [x] `(dl-query db '(ancestor tom X))` already worked — same query API
-      consumes the SX-data goal.
+      consumes the SX-data goal. Now also accepts a *list* of body
+      literals for conjunctive queries:
+      `(dl-query db '((p X) (q X)))`,
+      `(dl-query db (list '(n X) '(> X 2)))`. Auto-dispatched via
+      `dl-query-coerce` on first-element shape.
 - [x] `(dl-assert! db '(parent ann pat))` → adds the fact and re-saturates.
 - [x] `(dl-retract! db '(parent bob ann))` → drops matching tuples from
       the EDB list, wipes every relation that has a rule (those are IDB),
@@ -273,6 +277,14 @@ large graphs.
 
 _Newest first._
 
+- 2026-05-08 — `dl-query` accepts a list of body literals for
+  conjunctive queries, in addition to a single positive literal.
+  `dl-query-coerce` dispatches based on the first element's shape:
+  positive lit (head is a symbol) or `:neg` dict → wrap as singleton;
+  list of lits → use as-is. `dl-query-user-vars` collects the union
+  of vars across all goals (deduped, `_` filtered) for projection.
+  2 new api tests: multi-goal AND, and conjunction with comparison.
+
 - 2026-05-08 — Bug fix: `dl-check-stratifiable` now rejects recursion
   through aggregation (e.g., `q(N) :- count(N, X, q(X))`). The
   stratifier was already adding negation-like edges for aggregates,