feat: expand multiplayer, chat, and release support

- add network NPC synchronization and dialogue interactions
- add world bulletin publishing and display
- improve authentication, session refresh, and appearance sync
- synchronize player direction and movement animations
- improve input focus and progressive Web loading
- add macOS/Windows builds and deployment configuration
- include required fonts, shaders, and runtime assets

scripts/test_network_npc_animations.gd

@@ -0,0 +1,48 @@
+extends SceneTree
+
+const NETWORK_NPC_SCENE: PackedScene = preload("res://scenes/characters/network_npc.tscn")
+
+func _initialize() -> void:
+	call_deferred("_run")
+
+func _run() -> void:
+	var npc := NETWORK_NPC_SCENE.instantiate()
+	root.add_child(npc)
+	npc.call("apply_snapshot", {
+		"npcId": "npc_niulai",
+		"name": "牛来",
+		"scene": "niulai_ambassador",
+		"version": 1,
+		"x": 0,
+		"y": 0,
+		"movementState": "idle",
+	})
+	var animationPlayer := npc.get_node("AnimationPlayer") as AnimationPlayer
+	assert(npc.collision_layer == 2, "NPC must occupy the dedicated NPC collision layer")
+	assert(npc.collision_mask == 1, "NPC collision mask must include static map collision")
+	var npcShape := (npc.get_node("CollisionShape2D") as CollisionShape2D).shape as RectangleShape2D
+	assert(npcShape.size == Vector2(52, 24), "Niulai must use the adjusted physical footprint")
+	var nameplate := npc.get_node("Nameplate") as Label
+	assert(nameplate.get_theme_font_size("font_size") == 16, "NPC names must use the player name font size")
+	assert(nameplate.get_theme_constant("outline_size") == 3, "NPC names must use the player name outline")
+	assert(nameplate.get_theme_stylebox("normal") is StyleBoxEmpty, "NPC names must not use the old pill background")
+	npc.call("_configure_visual", "town_mayor")
+	assert(is_equal_approx(npc.nameplateOffsetY, -52.0), "The mayor name must follow the visible propeller instead of transparent frame padding")
+	npc.call("_configure_visual", "niulai_ambassador")
+	var library := animationPlayer.get_animation_library("")
+	var expectedRows := {"down": 0, "up": 1, "right": 2, "left": 3}
+	for direction in expectedRows:
+		var animationName := "walk_%s" % direction
+		assert(library.has_animation(animationName), "missing %s" % animationName)
+		var animation := library.get_animation(animationName)
+		assert(animation.loop_mode == Animation.LOOP_LINEAR, "%s must loop" % animationName)
+		assert(animation.track_get_key_count(0) == 4, "%s must contain four frames" % animationName)
+		for column in range(4):
+			assert(
+				animation.track_get_key_value(0, column) == expectedRows[direction] * 4 + column,
+				"%s uses the wrong spritesheet row" % animationName,
+			)
+	npc.call("interact")
+	assert(root.get_node_or_null("WorldChatBubbleLayer") == null, "NPC interaction must not create a world bubble layer")
+	print("NETWORK_NPC_ANIMATIONS_OK")
+	quit()