fix(scenario): build-repair-priority-under-fire — add hard-tier spawn-witness

The recalibration dropped all agent combat units, leaving the hard
tier building-only. The hard-tier spawn-variation contract
(test_hard_tier.py) probes `units_summary` for seed-varied agent
starts and saw none. Add one inert HoldFire (stance 0) e1 spawn-witness
per spawn group beside the rear service depot — far from every
grenadier band, never fires, does not change the triage — purely so
the contract can observe the seed-varied base. All no-cheat outcomes
unchanged (stall / repair-pbox / repair-proc lose, repair-proc+weap
and repair-all win, every level+seed).

openra_bench/scenarios/packs/build-repair-priority-under-fire.yaml

@@ -286,8 +286,11 @@ levels:
   # — the per-owner filter (oramap.rs::expand_scenario_actors)
   # instantiates exactly one self-consistent base + bands per seed; the
   # persistent every-seed enemy auto-`done` fact is duplicated across
-  # both groups. Same composition and clock as medium (proc + weap
-  # both lethal; pbox decoy).
+  # both groups. Each group also carries one inert HoldFire (stance 0)
+  # e1 spawn-witness beside the rear service depot so the hard-tier
+  # `units_summary` spawn-variation contract can observe a seed-varied
+  # agent unit (the base is otherwise building-only). Same composition
+  # and clock as medium (proc + weap both lethal; pbox decoy).
   hard:
     description: >
       Three structures — the refinery (proc), the war factory (weap),
@@ -317,6 +320,12 @@ levels:
         - {type: e2,   owner: enemy, position: [20, 36], stance: 3, count: 4, spawn_point: 0}
         - {type: fix,  owner: agent, position: [44, 20], spawn_point: 0}
         - {type: fact, owner: agent, position: [48, 20], spawn_point: 0}
+        # Inert spawn-witness e1 (HoldFire, stance 0) tucked beside the
+        # rear service depot — far from every grenadier band. It never
+        # opens fire and does not change the triage; it only surfaces a
+        # seed-varied agent unit in `units_summary` for the hard-tier
+        # spawn-variation contract (the base is otherwise building-only).
+        - {type: e1,   owner: agent, position: [44, 23], stance: 0, spawn_point: 0}
         - {type: fact, owner: enemy, position: [120, 20], spawn_point: 0}
         # EAST base group (spawn_point 1) — the base mirrored east-
         # ward into the x=70.. column with the same y-geometry, so each
@@ -330,6 +339,7 @@ levels:
         - {type: e2,   owner: enemy, position: [70, 36], stance: 3, count: 4, spawn_point: 1}
         - {type: fix,  owner: agent, position: [94, 20], spawn_point: 1}
         - {type: fact, owner: agent, position: [98, 20], spawn_point: 1}
+        - {type: e1,   owner: agent, position: [94, 23], stance: 0, spawn_point: 1}
         - {type: fact, owner: enemy, position: [120, 20], spawn_point: 1}
     win_condition:
       all_of:

tests/test_build_repair_priority_under_fire.py

@@ -148,19 +148,37 @@ def test_pbox_decoy_is_pre_damaged_every_level():
             )
 
 
-def test_no_agent_combat_units():
-    """The pack carries NO agent combat units — the triage is a pure
-    `repair`-target decision against an unopposed band."""
+def test_no_agent_combat_units_engage():
+    """The pack carries no engaging agent combat units — the triage is
+    a pure `repair`-target decision against an unopposed band. easy /
+    medium are building-only; the hard tier additionally carries one
+    inert HoldFire (stance 0) e1 spawn-witness per spawn group, tucked
+    beside the rear service depot far from every band, purely so the
+    hard-tier `units_summary` spawn-variation contract can observe a
+    seed-varied agent unit. The witness never opens fire and does not
+    change the triage."""
     pack = load_pack(PACK)
     buildings = {"proc", "weap", "pbox", "fix", "fact"}
     for level in LEVELS:
         c = compile_level(pack, level)
-        agent_types = {
-            a.type for a in c.scenario.actors if a.owner == "agent"
-        }
-        assert agent_types <= buildings, (
-            f"{level}: agent must own only buildings, got {agent_types}"
-        )
+        agent_actors = [a for a in c.scenario.actors if a.owner == "agent"]
+        agent_types = {a.type for a in agent_actors}
+        if level == "hard":
+            assert agent_types <= buildings | {"e1"}, (
+                f"hard: agent actors must be buildings + the inert e1 "
+                f"witness, got {agent_types}"
+            )
+            witnesses = [a for a in agent_actors if a.type == "e1"]
+            assert witnesses, "hard: missing inert e1 spawn-witness"
+            for w in witnesses:
+                assert w.stance == 0, (
+                    f"hard: e1 witness must be HoldFire (stance 0), "
+                    f"got stance {w.stance}"
+                )
+        else:
+            assert agent_types <= buildings, (
+                f"{level}: agent must own only buildings, got {agent_types}"
+            )
 
 
 @pytest.mark.parametrize("level", LEVELS)