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/scoreboard.md

@@ -1,6 +1,6 @@
 # mod scoreboard
 
-**277 / 277 passing** (0 failure(s)).
+**292 / 292 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -17,3 +17,4 @@
 | trace | 15 | 15 | ok |
 | whatif | 13 | 13 | ok |
 | batch | 17 | 17 | ok |
+| temporal | 15 | 15 | ok |