Hard-tier curation: adversarial family (skirmish, siege)

Both hard tiers reworked to two complete agent spawn_point groups
(upper-left / lower-left staging, wider randomize) so Env round-robins
the start axis by seed; enemy stays mid-map (fog-dependence); existing
fail_conditions retained. UPGRADED += skirmish, siege — live
seed→distinct-start integ check passes for all 3 adversarial packs.

openra_bench/scenarios/packs/adversarial-siege.yaml

@@ -77,9 +77,14 @@ levels:
         own_units_gte: 1
     max_turns: 75
   hard:
-    description: 'Rung 3 — dug-in mixed force, tight clock + loss cap.'
+    description: >
+      Rung 3 — dug-in mixed force, tight clock + loss cap, and the
+      assault force stages from a seed-chosen corner (two spawn_point
+      groups → the approach vector onto the entrenched position varies
+      by seed). Defenders sit mid-map beyond initial sight.
     overrides:
       actors:
+      # spawn_point 0 — full assault force, upper-left
       - type: 2tnk
         owner: agent
         position: [6, 10]
@@ -87,6 +92,24 @@ levels:
         health: 100
         facing: -1
         count: 5
+        spawn_point: 0
+        randomize:
+          position:
+            base: [6, 10]
+            offset: 3
+      # spawn_point 1 — full assault force, lower-left
+      - type: 2tnk
+        owner: agent
+        position: [6, 42]
+        stance: 3
+        health: 100
+        facing: -1
+        count: 5
+        spawn_point: 1
+        randomize:
+          position:
+            base: [6, 42]
+            offset: 3
       - type: e1
         owner: enemy
         position: [40, 26]

openra_bench/scenarios/packs/adversarial-skirmish.yaml

@@ -77,9 +77,14 @@ levels:
         own_units_gte: 1
     max_turns: 70
   hard:
-    description: 'Rung 3 — 3 tanks vs 8, loss-capped: maneuver or lose.'
+    description: >
+      Rung 3 — 3 tanks vs 8, loss-capped, and the outnumbered force
+      starts from a seed-chosen corner (two spawn_point groups → start
+      axis varies by seed, so a memorised kite line can't generalise).
+      Enemy is mid-map beyond initial sight: engage selection under fog.
     overrides:
       actors:
+      # spawn_point 0 — full force, upper-left
       - type: 2tnk
         owner: agent
         position: [6, 9]
@@ -87,6 +92,24 @@ levels:
         health: 100
         facing: -1
         count: 3
+        spawn_point: 0
+        randomize:
+          position:
+            base: [6, 9]
+            offset: 3
+      # spawn_point 1 — full force, lower-left (different approach)
+      - type: 2tnk
+        owner: agent
+        position: [6, 40]
+        stance: 3
+        health: 100
+        facing: -1
+        count: 3
+        spawn_point: 1
+        randomize:
+          position:
+            base: [6, 40]
+            offset: 3
       - type: e1
         owner: enemy
         position: [30, 20]

tests/test_hard_tier.py

@@ -25,6 +25,8 @@ PACKS = Path(__file__).parent.parent / "openra_bench" / "scenarios" / "packs"
 # economy-*/building-and-planning/strict-production-bom are N/A).
 UPGRADED = [
     "adversarial-duel",
+    "adversarial-skirmish",
+    "adversarial-siege",
 ]