Add shareware support and spawn correctly for difficulty levels

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/features/entities/enemies/enemy.dart

@@ -55,6 +55,28 @@ abstract class Enemy extends Entity {
     }
   }
 
+  void checkWakeUp({
+    required int elapsedMs,
+    required Coordinate2D playerPosition,
+    required bool Function(int x, int y) isWalkable,
+    int baseReactionMs = 200,
+    int reactionVarianceMs = 600,
+  }) {
+    if (state == EntityState.idle &&
+        hasLineOfSight(playerPosition, isWalkable)) {
+      if (reactionTimeMs == 0) {
+        reactionTimeMs =
+            elapsedMs +
+            baseReactionMs +
+            math.Random().nextInt(reactionVarianceMs);
+      } else if (elapsedMs >= reactionTimeMs) {
+        state = EntityState.patrolling;
+        lastActionTime = elapsedMs;
+        reactionTimeMs = 0;
+      }
+    }
+  }
+
   // Matches WL_STATE.C's 'CheckLine' using canonical Integer DDA traversal
   bool hasLineOfSight(
     Coordinate2D playerPosition,
@@ -63,7 +85,7 @@ abstract class Enemy extends Entity {
     // 1. Proximity Check (Matches WL_STATE.C 'MINSIGHT')
     // If the player is very close, sight is automatic regardless of facing angle.
     // This compensates for our lack of a noise/gunshot alert system!
-    if (position.distanceTo(playerPosition) < 2.0) {
+    if (position.distanceTo(playerPosition) < 1.2) {
       return true;
     }