mod: Ext 12 — temporal burst detection, 292/292

Reports gain an :at tick (deterministic, supplied). mod/decide-temporal counts
reports about a subject within [now-window, now], asserts burst_count/2, and a
(:burst-at-least K) rule fires only on a real burst. 3 reports at 10/11/12 → hide;
3 at 1/2/12 (window 5) → keep, while the plain count rule escalates both. Fifth
report field threaded through rebuild helpers, non-breaking. +15 tests.

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

lib/mod/policy.sx

@@ -49,6 +49,8 @@
 ;; (:reporters-at-least 2)   → report(Id, _, Sr), setof(Br, report(_, Br, Sr), Bsr),
 ;;                             length(Bsr, Nr), Nr >= 2   (distinct reporters;
 ;;                             needs the quorum engine which asserts every report)
+;; (:burst-at-least 3)       → report(Id, _, Sb), burst_count(Sb, Nb), Nb >= 3
+;;                             (reports in a time window; needs the temporal engine)
 
 (define
   mod/cond->goal
@@ -88,6 +90,12 @@
             ", _, Sr), setof(Br, report(_, Br, Sr), Bsr), "
             "length(Bsr, Nr), Nr >= "
             (nth c 1)))
+        ((= tag :burst-at-least)
+          (str
+            "report("
+            idterm
+            ", _, Sb), burst_count(Sb, Nb), Nb >= "
+            (nth c 1)))
         (true "true")))))
 
 (define