feat(ai): ✨ Enhance military unit detection logic in SimpleHeuristicAI for improved strategic accuracy

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

src/game/engine/src/modules/ai/simple_heuristic_ai.gd

@@ -56,7 +56,11 @@ static func process_player(player: RefCounted) -> Array:
 		var action: Dictionary = {}
 		if unit.can_found_city:
 			action = _decide_founder_action(idx, unit, player, enemy_units)
-		elif unit.unit_type in MILITARY_COMBAT_TYPES:
+		elif unit.attack > 0 or unit.ranged_attack > 0:
+			# Stat-based dispatch — `unit.unit_type` is read from a JSON field
+			# (`combat_type`) that the current data files don't populate, so it
+			# would always be empty here. Anything with combat stats and no
+			# founder flag is treated as a military unit.
 			action = _decide_military_action(
 				idx,
 				unit,