fix(client): make E2E tests resilient to entity ordering

Server proof room now has 3 NPCs instead of 1. Find player entity
by kind instead of assuming entities[0]. Wall-hides test checks
specific NPC position (16.5, 13.5) rather than asserting zero NPC
count. Corner-reveal test searches for NPC1 by position.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/tests/test_e2e_connection.gd

@@ -109,12 +109,18 @@ func test_send_input_receive_snapshot() -> void:
 
 	# Server starts at tick 0, snapshot reflects state after processing
 	assert_that(snapshot.tick).is_equal(0)
-	assert_that(snapshot.entities.size()).is_equal(1)
+	assert_that(snapshot.entities.size()).is_greater(0)
+
+	# Find the player entity by kind (entity order is not guaranteed)
+	var player: Dictionary = {}
+	for entity in snapshot.entities:
+		if entity.kind.variant == "Player":
+			player = entity
+			break
+	assert_that(player.size()).is_greater(0)
 
 	# Player started at (16, 16, 0), moved north (y-1) to (16, 15, 0)
 	# Render coords: tile center offset -> (16.5, 15.5, 0)
-	var player: Dictionary = snapshot.entities[0]
 	assert_float(player.x).is_equal_approx(16.5, 0.001)
 	assert_float(player.y).is_equal_approx(15.5, 0.001)
 	assert_that(player.z).is_equal(0)
-	assert_that(player.kind.variant).is_equal("Player")

client/tests/test_sprint2_proof.gd

@@ -6,9 +6,10 @@
 ## Requires: server binary built (cargo build in server/)
 ##
 ## Server proof room layout:
-##   (16,13) = NPC    (16,14) = WALL    (16,16) = Player start
-##   Player facing North → NPC blocked by wall.
-##   Move East+North around the wall → NPC becomes visible.
+##   (16,13) = NPC1   (16,14) = WALL    (16,16) = Player start
+##   (14,18) = NPC2   (18,14) = NPC3
+##   Player facing North → NPC1 blocked by wall.
+##   Move East+North around the wall → NPC1 becomes visible.
 class_name TestSprint2Proof
 extends GdUnitTestSuite
 
@@ -118,13 +119,17 @@ func test_proof_player_moves_and_v2_snapshot() -> void:
 	var snapshot: Dictionary = await _send_and_receive("MoveNorth")
 
 	# AC#1: Player moved from (16,16) to (16,15)
-	var player: Dictionary = snapshot.entities[0]
+	var player: Dictionary = {}
+	for entity in snapshot.entities:
+		if entity.kind.variant == "Player":
+			player = entity
+			break
+	assert_that(player.size()).is_greater(0)
 	assert_float(player.x).is_equal_approx(16.5, 0.001)
 	assert_float(player.y).is_equal_approx(15.5, 0.001)
-	assert_that(player.kind.variant).is_equal("Player")
 
-	# v2 protocol fields present
-	assert_that(snapshot.version).is_equal(2)
+	# v4 protocol fields present
+	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 	assert_that(snapshot.player_facing).is_equal("North")
 	assert_that(snapshot.game_time).is_not_null()
 
@@ -143,15 +148,18 @@ func test_proof_wall_hides_entity() -> void:
 		return
 
 	# After MoveNorth: player at (16,15) facing North.
-	# Wall at (16,14) blocks LOS to NPC at (16,13).
+	# Wall at (16,14) blocks LOS to NPC1 at (16,13).
 	var snapshot: Dictionary = await _send_and_receive("MoveNorth")
 
-	# Only player should be visible — NPC is behind wall
-	var npc_count := 0
+	# NPC1 at (16,13) should be hidden — wall at (16,14) blocks LOS.
+	# Other NPCs (NPC2 at (14,18), NPC3 at (18,14)) may be visible.
+	var hidden_npc_visible := false
 	for entity in snapshot.entities:
 		if entity.kind.variant == "Npc":
-			npc_count += 1
-	assert_that(npc_count).is_equal(0)
+			if is_equal_approx(entity.x, 16.5) and is_equal_approx(entity.y, 13.5):
+				hidden_npc_visible = true
+				break
+	assert_that(hidden_npc_visible).is_false()
 
 
 # -- AC#4, AC#7: Entity appears via LOS / corner reveal ----------------------------
@@ -172,13 +180,12 @@ func test_proof_corner_reveal() -> void:
 	await _send_and_receive("MoveNorth", 3)
 	var snapshot: Dictionary = await _send_and_receive("MoveNorth", 4)
 
-	# Player at (18,13) facing North. NPC at (16,13) is 2 tiles west —
-	# within peripheral cone, no wall between. NPC should be visible.
-	var npc_found := false
+	# Player at (18,13) facing North. NPC1 at (16,13) is 2 tiles west —
+	# within peripheral cone, no wall between. NPC1 should be visible.
+	var npc1_found := false
 	for entity in snapshot.entities:
 		if entity.kind.variant == "Npc":
-			assert_float(entity.x).is_equal_approx(16.5, 0.001)
-			assert_float(entity.y).is_equal_approx(13.5, 0.001)
-			npc_found = true
-			break
-	assert_that(npc_found).is_true()
+			if is_equal_approx(entity.x, 16.5) and is_equal_approx(entity.y, 13.5):
+				npc1_found = true
+				break
+	assert_that(npc1_found).is_true()