forgetest: verdict-cut holds the daemon under the report dead-man

laser.verdict-cut freezes the daemon so the verdict the controller
caches expires and the driver's pause tier holds the job, then resumes
and proves the job ran dark through the hold with the laser latch never
locked. The freeze was 3.5 s. The engine's report dead-man locks the
laser latch when the controller's report is older than 5.0 s while
armed, and the last report is up to 1 s old when the freeze starts, so
a 3.5 s freeze left only a half second of margin - a dead-man latch
lock reads exactly like the failure the test refuses.

The freeze is now 3.0 s: still past the 2.0 s the cached verdict takes
to expire (so the pause tier holds and the hold is seen), a full second
under the dead-man. No behavior changed, only the freeze the test
holds.

forgetest/forgetest/suite/laser.py

@@ -861,7 +861,16 @@ def verdict_cut(ctx):
     import signal as _signal
     ev = ctx.evidence
     fc = ctx.forgectrl
-    PAUSE_S = 3.5
+    # The daemon is frozen long enough for the verdict the controller
+    # caches to expire (VERDICT_MAX_AGE 2.0 s), so the driver's pause tier
+    # holds the job - but not so long that the engine's report dead-man
+    # trips on resume. That dead-man locks the laser latch when the
+    # controller's report is older than REPORT_TIMEOUT_S (5.0 s) while
+    # armed, which is exactly the "latch stayed locked" this test refuses.
+    # The last report is up to 1 s old when the freeze starts, so the
+    # freeze must stay under 4.0 s; 3.0 s clears the stale floor with room
+    # to see the hold and stays a full second under the dead-man.
+    PAUSE_S = 3.0
     pids = hw.pidof("forgectrl")
     ctx.check(pids, "no forgectrl process found to pause")
     ev["daemon_pids"] = pids