feat(client): 完成40250客户端核心功能1:1对齐与桥梁高度采样修复

- 桥梁与静态物体高度采样修复：
  - 严格对齐 40250 CMapOutdoor::GetHeight 与 CAttributeInstance::GetHeight
  - 解析 .mdatr 中的 AttributeHeight 网格，使用 is_in_triangle_2d 准确计算桥面多边形平面方程
  - sample_height 查询邻近区块并返回 fMAX(fObjectHeight, fTerrainHeight)，彻底解决走上桥面穿透掉入水底/河床的问题
  - 新增 test_bridge_height_parity.gd 自动化对拍测试
- 40250 怪物击杀经验动效：
  - 1:1 实现 FLY_EXP(0) / FLY_HP / FLY_SP 粒子轨迹与爆炸吸附
- 40250 客户端全系统功能对齐（Batches 1-31）：
  - 包含公会、交易、骑乘、变身、钓鱼、采矿、商城、信件、结婚、地牢等 134 套对拍系统与自动化回归测试
- 文档沉淀：
  - 新增 docs/CLIENT-PARITY-AUDIT-AND-FIX-GUIDE.md 客户端对拍缺陷发现与修复工程指南

project/char_select_visual_test.gd

@@ -63,6 +63,9 @@ func _run() -> void:
 	if hair_image != null:
 		hair_image.save_png(output.path_join("hair-texture.png"))
 	var mesh_bounds: Array = []
+	var body_uses_blue_steel_skin := false
+	var blue_steel_path := AssetRoot.path().path_join("patch2/ymir work/pc/warrior/warrior_4-2.dds")
+	var blue_steel_image: Image = ua.load_dds_image(blue_steel_path) if main_part == 12019 else null
 	for mi in screen._pv.find_children("*", "MeshInstance3D", true, false):
 		var local_aabb: AABB = mi.get_aabb()
 		var world_aabb: AABB = mi.get_global_transform() * local_aabb
@@ -78,6 +81,17 @@ func _run() -> void:
 			var mat: Material = mi.get_active_material(surface)
 			if mat is ShaderMaterial:
 				print("MATERIAL mode=", mat.get_shader_parameter("mode"), " alpha_write=", mat.shader.code.contains("ALPHA ="))
+				var albedo := mat.get_shader_parameter("albedo_tex") as Texture2D
+				if albedo and blue_steel_image:
+					var actual := albedo.get_image()
+					# Character textures generate mipmaps before upload. Compare only
+					# level 0 with the decoded DDS or identical pixels would differ by
+					# the appended mip levels.
+					var expected_data := blue_steel_image.get_data()
+					var actual_data := actual.get_data() if actual else PackedByteArray()
+					if actual and actual.get_size() == blue_steel_image.get_size() \
+							and actual_data.slice(0, expected_data.size()) == expected_data:
+						body_uses_blue_steel_skin = true
 				if "--solid-body" in OS.get_cmdline_user_args():
 					var solid := StandardMaterial3D.new()
 					solid.albedo_texture = mat.get_shader_parameter("albedo_tex")
@@ -87,12 +101,23 @@ func _run() -> void:
 		printerr("FAIL: server armor was not applied")
 		quit(1)
 		return
+	if main_part == 12019 and not body_uses_blue_steel_skin:
+		printerr("FAIL: armor 12019 geometry loaded without warrior_4-2 target skin")
+		quit(1)
+		return
 	if hair_part == 1001 and not String(screen._pv.model.get("hair_gr2")).to_lower().contains("hair_2_1"):
 		printerr("FAIL: standard HairIndex 1001 did not replace the default hair model")
 		quit(1)
 		return
 	if DisplayServer.get_name() != "headless":
 		await RenderingServer.frame_post_draw
+		if screen._viewport:
+			var viewport_image := screen._viewport.get_texture().get_image()
+			if viewport_image.detect_alpha() != Image.ALPHA_NONE:
+				printerr("FAIL: selection stage must be opaque; transparent additive particles create black quads")
+				quit(1)
+				return
+			viewport_image.save_png(output.path_join("viewport.png"))
 		if root.get_texture().get_image().save_png(output.path_join("selection.png")) != OK:
 			quit(1)
 			return