Hazard: destructible cover — carve-able rocks that genuinely block until broken

Phase 1.5 long-term #8, the LAST 1.5 item (design review wf_e14dd739-069:
both HIGHs + the distinct MEDs verified before the session limit ate the
duplicate verifiers; unverified leftovers reasoned-closed in the spec).

Cover = a BlightClutter ghost (Variant 4) with a baked Environment-layer
BoxCollider: the runtime ghost's collider joins BuildPhysicsWorld ->
blocks the player CC and the enemy sweep while alive, and the gap opens
the instant the entity dies. Both hit paths already break it (the
clutter chassis); 8 hits to carve.

Review folds:
- HIGH: the 07-07 anti-stuck nudge would phase enemies THROUGH cover
  after ~1.5s (it exists to prevent room soft-locks). The nudge is now
  COVER-AWARE: a SphereCast identifies the blocker; a live BlightClutter
  ghost suppresses the phase (no soft-lock possible - the blocker is
  destructible); static-geometry wedges still nudge.
- HIGH: yield==durability made tanky cover an economy faucet. Deposit
  is DECOUPLED from the decrement at both hit sites: ScrapPerHit=0 =
  breaks in Remaining hits, yields NOTHING; fractional POSITIVE yields
  still credit >=1 (the B1 immortal-sink test pinned this - zero means
  zero, positive floors to 1).
- MEDs: HitRadius 1.2 (visual core, not a shot-eating disc), NO cover
  in Boss rooms (no boss depenetration backstop), scatter keep-out >=7u
  from the room origin (player landing + portal), Variant=4 explicit
  (the clutter block's explosive reroll cannot leak).
- Old static layer removed: 8 WorldColliders_RoomCover colliders
  (subscene) + the RoomCover_Visuals root (Game.unity).

Verified live: 3 cover ghosts spawned with SOLID baked colliders;
BLOCK - NudgeUntilTick stayed 0 across 3.5s of forced zero-progress
(old code arms at 1.5s); DEPENETRATE - an enemy shoved inside a live
rock exited to 1.7u (backstop holds against ghost colliders); CARVE -
the rock died to the real sweep and the spot probed OPEN. 470/470
EditMode; console clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/_Project/Scripts/Server/Combat/EnemyAISystem.cs

@@ -630,8 +630,24 @@ namespace ProjectM.Server
                     nav.ValueRW.LastPos = npos;
                     if (st >= StuckUnstickTicks)
                     {
-                        nav.ValueRW.NudgeUntilTick = TickUtil.NonZero(now + NudgeBurstTicks);
-                        st = 0u;
+                        // COVER-AWARE (destructible-cover review wf_e14dd739-069 HIGH): if what blocks this enemy
+                        // is a LIVE cover GHOST (BlightClutter carrier), do NOT phase-nudge — cover must genuinely
+                        // hold until the player breaks it. No soft-lock is possible: the blocker is destructible,
+                        // and the counter stays primed so any OTHER wedge (static geometry) still nudges next check.
+                        bool blockedByCover = false;
+                        if (havePhysics)
+                        {
+                            float3 toTgt = nTarget - npos; toTgt.y = 0f;
+                            float tl = math.length(toTgt);
+                            if (tl > 1e-4f && physics.CollisionWorld.SphereCast(
+                                    npos, 0.35f, toTgt / tl, math.min(1.8f, tl), out var coverHit, envFilter))
+                                blockedByCover = SystemAPI.HasComponent<BlightClutter>(coverHit.Entity);
+                        }
+                        if (!blockedByCover)
+                        {
+                            nav.ValueRW.NudgeUntilTick = TickUtil.NonZero(now + NudgeBurstTicks);
+                            st = 0u;
+                        }
                     }
                     nav.ValueRW.StuckTicks = st;
                 }