Correlator prompt: show incident age/size, stop unit overlap chaining new jobs (#189)

The tiebreaker forced ~all of the 09-27 rollover sink's bad links: idle resets
on every link so a 2.5h, 40-call incident read as fresh, and the rules treated
unit overlap as enough on a county channel where units work jobs back to back.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-c2-core/tests/test_correlator_115.py

@@ -65,3 +65,16 @@ def test_prompt_incidents_is_most_recently_active_first_and_capped():
     # falls back to started_at when updated_at is absent, and never raises
     assert _prompt_incidents([{"incident_id": "a", "started_at": NOW.isoformat()},
                               {"incident_id": "b"}])[0]["incident_id"] == "a"
+
+
+def test_inc_summary_shows_age_and_size_not_just_idle():
+    # server-26#189: every link resets idle, so a 2.5h catch-all read as fresh.
+    s = _inc_summary({
+        "incident_id": "sink",
+        "started_at": "2026-09-07T05:26:00+00:00",
+        "updated_at": "2026-09-07T07:58:00+00:00",
+        "call_ids": [f"c{n}" for n in range(40)],
+    }, NOW)
+    assert "idle:2min ago" in s
+    assert "open:2h34m" in s
+    assert "calls:40" in s