feat(client): protocol v6 bridge — stance, inventory, input mapping

Upgrade client protocol bridge from v5 to v6 to match server.
Adds player_stance (4 variants) and player_inventory decode to
ObserverSnapshot. Adds TOGGLE_STANCE_UP/DOWN to InputMapper.
Includes 25 gdUnit4 tests for v6 decode + server serialization
test gap fix.

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

client/scripts/autoloads/game_state.gd

@@ -25,6 +25,10 @@ var nearby_interactions: Array = []  # [{entity_id, entity_type, distance, verbs
 # v5 fields (#414)
 var current_monologue: Variant = null  # {id, text, duration_seconds} or null
 
+# v6 fields (#449, D-053, D-065)
+var player_stance: String = "Walk"  # Sprint/Walk/Careful/Crouch
+var player_inventory: Array = []  # [{item_id, name, slot}]
+
 func apply_snapshot(snapshot: Dictionary) -> void:
 	current_snapshot = snapshot
 
@@ -82,6 +86,16 @@ func apply_snapshot(snapshot: Dictionary) -> void:
 	else:
 		current_monologue = null
 
+	# v6: player_stance (#449, D-053)
+	if snapshot.has("player_stance") and snapshot.player_stance is String:
+		player_stance = snapshot.player_stance
+
+	# v6: player_inventory (#449, D-065)
+	if snapshot.has("player_inventory") and snapshot.player_inventory is Array:
+		player_inventory = snapshot.player_inventory
+	else:
+		player_inventory = []
+
 	# v2: visible_tiles with visibility sectors
 	# Derives visible_positions when not explicitly provided (real server mode)
 	if snapshot.has("visible_tiles") and snapshot.visible_tiles is Array and snapshot.visible_tiles.size() > 0:

client/scripts/autoloads/input_mapper.gd

@@ -6,7 +6,8 @@ extends Node
 enum Action {
 	MOVE_NORTH, MOVE_NORTHEAST, MOVE_EAST, MOVE_SOUTHEAST,
 	MOVE_SOUTH, MOVE_SOUTHWEST, MOVE_WEST, MOVE_NORTHWEST,
-	INTERACT, USE_PERCEPTION_MODE, OPEN_MENU, PAUSE
+	INTERACT, USE_PERCEPTION_MODE, OPEN_MENU, PAUSE,
+	TOGGLE_STANCE_UP, TOGGLE_STANCE_DOWN,
 }
 
 var input_queue: Array[Dictionary] = []
@@ -40,6 +41,10 @@ func _unhandled_input(event: InputEvent) -> void:
 		action = Action.OPEN_MENU
 	elif event.is_action_pressed("pause"):
 		action = Action.PAUSE
+	elif event.is_action_pressed("stance_up"):
+		action = Action.TOGGLE_STANCE_UP
+	elif event.is_action_pressed("stance_down"):
+		action = Action.TOGGLE_STANCE_DOWN
 
 	# Queue the action if valid
 	if action != -1:

client/scripts/autoloads/sim_bridge.gd

@@ -242,6 +242,8 @@ static func _action_enum_to_wire(action: int) -> String:
 		InputMapper.Action.INTERACT: return "Interact"
 		InputMapper.Action.USE_PERCEPTION_MODE: return "UsePerceptionMode"
 		InputMapper.Action.PAUSE: return "Pause"
+		InputMapper.Action.TOGGLE_STANCE_UP: return "ToggleStanceUp"
+		InputMapper.Action.TOGGLE_STANCE_DOWN: return "ToggleStanceDown"
 		InputMapper.Action.OPEN_MENU:
 			# Client-only action, not part of wire protocol
 			push_warning("SimBridge: OPEN_MENU is client-only, not sent to server")
@@ -328,6 +330,8 @@ func _test_snapshot() -> Dictionary:
 			"tick_rate": "Full",
 		},
 		"player_facing": _test_facing,
+		"player_stance": "Walk",
+		"player_inventory": [],
 		"entities": entities,
 		"tiles": _test_tiles(),
 		"visible_tiles": _test_visible_tiles(),

client/scripts/protocol/protocol.gd

@@ -11,7 +11,7 @@ class_name Protocol
 
 ## Protocol version — must match server PROTOCOL_VERSION in bridge/types.rs.
 ## Reject snapshots where version != this value.
-const PROTOCOL_VERSION: int = 5
+const PROTOCOL_VERSION: int = 6
 
 
 # -- Decode: bytes from server → GDScript types --------------------------------
@@ -104,6 +104,24 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 			"duration_seconds": float(raw_monologue.get("duration_seconds", 5.0)),
 		}
 
+	# v6: player_stance (#449, D-053) — unit enum → bare string
+	var player_stance: String = "Walk"
+	var raw_stance: Variant = raw.get("player_stance")
+	if raw_stance is String:
+		player_stance = raw_stance
+
+	# v6: player_inventory (#449, D-065) — array of {item_id, name, slot}
+	var player_inventory: Array = []
+	var raw_inventory: Variant = raw.get("player_inventory")
+	if raw_inventory is Array:
+		for raw_item in raw_inventory:
+			if raw_item is Dictionary and raw_item.has("item_id") and raw_item.has("name"):
+				player_inventory.append({
+					"item_id": int(raw_item["item_id"]),
+					"name": str(raw_item["name"]),
+					"slot": int(raw_item.get("slot", 0)),
+				})
+
 	return {
 		"tick": tick,
 		"entities": entities,
@@ -111,6 +129,8 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		"version": version,
 		"game_time": game_time,
 		"player_facing": player_facing,
+		"player_stance": player_stance,
+		"player_inventory": player_inventory,
 		"visible_tiles": visible_tiles,
 		"nearby_interactions": nearby_interactions,
 		"current_monologue": current_monologue,

client/tests/test_protocol.gd

@@ -280,7 +280,7 @@ func test_decode_snapshot_v2_full() -> void:
 
 	assert_that(snapshot).is_not_null()
 	assert_that(snapshot.tick).is_equal(500)
-	assert_that(snapshot.version).is_equal(4)
+	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
 
 	# game_time
 	assert_that(snapshot.game_time).is_not_null()
@@ -307,7 +307,7 @@ func test_existing_fixtures_have_v2_fields() -> void:
 		var bytes = _load_fixture(fixture_name)
 		var snapshot = Protocol.decode_snapshot(bytes)
 		assert_that(snapshot).is_not_null()
-		assert_that(snapshot.version).is_equal(4)
+		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()
 

client/tests/test_protocol_v6.gd

@@ -0,0 +1,394 @@
+## D-030 Layer 1: Protocol v6 tests for ObserverSnapshot bridge upgrade (#449).
+## Validates player_stance (D-053) and player_inventory (D-065) decode,
+## GameState storage, SimBridge test mode, and input encoding for stance toggles.
+## Spec refs: D-053, D-065, D-020, #449
+class_name TestProtocolV6
+extends GdUnitTestSuite
+
+const FIXTURE_DIR = "res://tests/fixtures/msgpack/"
+
+
+func _load_fixture(name: String) -> PackedByteArray:
+	var path = FIXTURE_DIR + name + ".msgpack"
+	var file = FileAccess.open(path, FileAccess.READ)
+	assert_that(file).is_not_null()
+	return file.get_buffer(file.get_length())
+
+
+# -- Protocol version upgrade -------------------------------------------------
+
+func test_protocol_version_is_6() -> void:
+	assert_that(Protocol.PROTOCOL_VERSION).is_equal(6)
+
+
+func test_fixtures_at_protocol_version_6() -> void:
+	# All regenerated fixtures should be at v6
+	for fixture_name in ["snapshot_one_npc", "snapshot_empty", "snapshot_player", "snapshot_multi_entity"]:
+		var bytes = _load_fixture(fixture_name)
+		var snapshot = Protocol.decode_snapshot(bytes)
+		assert_that(snapshot).is_not_null()
+		assert_that(snapshot.version).is_equal(6)
+
+
+func test_rejects_version_5() -> void:
+	var raw := {"tick": 1, "version": 5, "entities": []}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot).is_null()
+
+
+# -- player_stance decode (D-053) ---------------------------------------------
+
+func test_decode_player_stance_walk() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Walk",
+		"player_inventory": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot).is_not_null()
+	assert_that(snapshot.player_stance).is_equal("Walk")
+
+
+func test_decode_player_stance_sprint() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Sprint",
+		"player_inventory": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_stance).is_equal("Sprint")
+
+
+func test_decode_player_stance_careful() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Careful",
+		"player_inventory": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_stance).is_equal("Careful")
+
+
+func test_decode_player_stance_crouch() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Crouch",
+		"player_inventory": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_stance).is_equal("Crouch")
+
+
+func test_decode_player_stance_missing_defaults_to_walk() -> void:
+	# v6 snapshot without player_stance → should default to "Walk"
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot).is_not_null()
+	assert_that(snapshot.player_stance).is_equal("Walk")
+
+
+# -- player_inventory decode (D-065) ------------------------------------------
+
+func test_decode_empty_inventory() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Walk",
+		"player_inventory": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_inventory.size()).is_equal(0)
+
+
+func test_decode_smuggler_inventory_3_items() -> void:
+	# D-065: smuggler carries 3 specific items
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_stance": "Walk",
+		"player_inventory": [
+			{"item_id": 100, "name": "Manifest Copy", "slot": 0},
+			{"item_id": 101, "name": "Access Token", "slot": 1},
+			{"item_id": 102, "name": "Comm Log", "slot": 2},
+		],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+
+	assert_that(snapshot.player_inventory.size()).is_equal(3)
+	assert_that(snapshot.player_inventory[0].item_id).is_equal(100)
+	assert_that(snapshot.player_inventory[0].name).is_equal("Manifest Copy")
+	assert_that(snapshot.player_inventory[0].slot).is_equal(0)
+	assert_that(snapshot.player_inventory[1].name).is_equal("Access Token")
+	assert_that(snapshot.player_inventory[1].slot).is_equal(1)
+	assert_that(snapshot.player_inventory[2].name).is_equal("Comm Log")
+	assert_that(snapshot.player_inventory[2].slot).is_equal(2)
+
+
+func test_decode_full_9_slot_inventory() -> void:
+	# D-065: 3x3 grid = 9 slots universal
+	var items: Array = []
+	for i in range(9):
+		items.append({"item_id": 100 + i, "name": "Item %d" % i, "slot": i})
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_inventory": items,
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+
+	assert_that(snapshot.player_inventory.size()).is_equal(9)
+	assert_that(snapshot.player_inventory[0].slot).is_equal(0)
+	assert_that(snapshot.player_inventory[8].slot).is_equal(8)
+	assert_that(snapshot.player_inventory[8].item_id).is_equal(108)
+
+
+func test_decode_inventory_missing_defaults_to_empty() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_inventory.size()).is_equal(0)
+
+
+func test_decode_inventory_skips_malformed_items() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_inventory": [
+			{"item_id": 100, "name": "Valid Item", "slot": 0},
+			{"broken": true},  # Missing item_id and name
+			{"item_id": 101},  # Missing name
+			{"name": "No ID"},  # Missing item_id
+			{"item_id": 102, "name": "Also Valid", "slot": 3},
+		],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	# Only items with both item_id and name should decode
+	assert_that(snapshot.player_inventory.size()).is_equal(2)
+	assert_that(snapshot.player_inventory[0].name).is_equal("Valid Item")
+	assert_that(snapshot.player_inventory[1].name).is_equal("Also Valid")
+
+
+func test_decode_inventory_item_slot_defaults_to_zero() -> void:
+	var raw := {
+		"tick": 1,
+		"version": Protocol.PROTOCOL_VERSION,
+		"entities": [],
+		"player_inventory": [
+			{"item_id": 100, "name": "No Slot"},
+		],
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+	assert_that(snapshot.player_inventory[0].slot).is_equal(0)
+
+
+# -- GameState: v6 field storage -----------------------------------------------
+
+func test_game_state_stores_player_stance() -> void:
+	GameState.apply_snapshot({"tick": 1, "entities": [], "player_stance": "Sprint"})
+	assert_that(GameState.player_stance).is_equal("Sprint")
+	GameState.player_stance = "Walk"  # Reset
+
+
+func test_game_state_stores_player_inventory() -> void:
+	var inv := [
+		{"item_id": 100, "name": "Manifest Copy", "slot": 0},
+		{"item_id": 101, "name": "Access Token", "slot": 1},
+	]
+	GameState.apply_snapshot({"tick": 1, "entities": [], "player_inventory": inv})
+	assert_that(GameState.player_inventory.size()).is_equal(2)
+	assert_that(GameState.player_inventory[0].name).is_equal("Manifest Copy")
+	GameState.player_inventory = []  # Reset
+
+
+func test_game_state_clears_inventory_when_absent() -> void:
+	var inv := [{"item_id": 100, "name": "Item", "slot": 0}]
+	GameState.apply_snapshot({"tick": 1, "entities": [], "player_inventory": inv})
+	assert_that(GameState.player_inventory.size()).is_equal(1)
+	GameState.apply_snapshot({"tick": 2, "entities": []})
+	assert_that(GameState.player_inventory.size()).is_equal(0)
+
+
+func test_game_state_stance_persists_when_absent() -> void:
+	# Stance should NOT reset when field is missing — keep last known value
+	GameState.apply_snapshot({"tick": 1, "entities": [], "player_stance": "Careful"})
+	assert_that(GameState.player_stance).is_equal("Careful")
+	GameState.apply_snapshot({"tick": 2, "entities": []})
+	# Stance persists (no explicit reset to Walk when absent)
+	assert_that(GameState.player_stance).is_equal("Careful")
+	GameState.player_stance = "Walk"  # Reset
+
+
+func test_game_state_defaults() -> void:
+	# Default values before any snapshot
+	var gs_stance = GameState.player_stance
+	var gs_inv = GameState.player_inventory
+	assert_that(gs_stance).is_equal("Walk")
+	assert_that(gs_inv.size()).is_equal(0)
+
+
+# -- SimBridge test mode: v6 fields -------------------------------------------
+
+func test_sim_bridge_test_snapshot_has_player_stance() -> void:
+	SimBridge.reset_test_state()
+	var snap = SimBridge._test_snapshot()
+	assert_that(snap.has("player_stance")).is_true()
+	assert_that(snap.player_stance).is_equal("Walk")
+
+
+func test_sim_bridge_test_snapshot_has_player_inventory() -> void:
+	SimBridge.reset_test_state()
+	var snap = SimBridge._test_snapshot()
+	assert_that(snap.has("player_inventory")).is_true()
+	assert_that(snap.player_inventory is Array).is_true()
+
+
+func test_sim_bridge_test_snapshot_version_6() -> void:
+	SimBridge.reset_test_state()
+	var snap = SimBridge._test_snapshot()
+	assert_that(snap.version).is_equal(6)
+
+
+# -- Fixture: v6 snapshots include new fields ----------------------------------
+
+func test_fixture_snapshots_have_v6_defaults() -> void:
+	# All regenerated fixtures should have player_stance=Walk and empty inventory
+	for fixture_name in ["snapshot_one_npc", "snapshot_empty", "snapshot_player"]:
+		var bytes = _load_fixture(fixture_name)
+		var snapshot = Protocol.decode_snapshot(bytes)
+		assert_that(snapshot).is_not_null()
+		assert_that(snapshot.player_stance).is_equal("Walk")
+		assert_that(snapshot.player_inventory.size()).is_equal(0)
+
+
+# -- Input encoding: stance toggle actions (D-053) ----------------------------
+
+func test_encode_toggle_stance_up() -> void:
+	var inputs: Array = [{"tick": 10, "action_name": "ToggleStanceUp"}]
+	var bytes := Protocol.encode_player_inputs(inputs)
+	var raw = Messagepack.decode(bytes)
+	assert_that(raw.status == null).is_true()
+	assert_that(raw.value[0]["action"]).is_equal("ToggleStanceUp")
+
+
+func test_encode_toggle_stance_down() -> void:
+	var inputs: Array = [{"tick": 10, "action_name": "ToggleStanceDown"}]
+	var bytes := Protocol.encode_player_inputs(inputs)
+	var raw = Messagepack.decode(bytes)
+	assert_that(raw.status == null).is_true()
+	assert_that(raw.value[0]["action"]).is_equal("ToggleStanceDown")
+
+
+func test_encode_decode_stance_toggle_roundtrip() -> void:
+	for action_name in ["ToggleStanceUp", "ToggleStanceDown"]:
+		var bytes = Protocol.encode_player_input(50, action_name)
+		assert_that(bytes.size()).is_greater(0)
+		var decoded = Protocol.decode_player_input(bytes)
+		assert_that(decoded).is_not_null()
+		assert_that(decoded.tick).is_equal(50)
+		assert_that(decoded.action.variant).is_equal(action_name)
+		assert_that(decoded.action.data).is_null()
+
+
+# -- Integration: full v6 snapshot round-trip ----------------------------------
+
+func test_full_v6_snapshot_decode() -> void:
+	# Simulate a realistic v6 snapshot with all fields populated
+	var raw := {
+		"tick": 100,
+		"version": Protocol.PROTOCOL_VERSION,
+		"game_time": {"day": 1, "time_of_day": 720, "day_phase": "Evening", "tick_rate": "Full"},
+		"player_facing": "Southeast",
+		"player_stance": "Careful",
+		"player_inventory": [
+			{"item_id": 100, "name": "Manifest Copy", "slot": 0},
+			{"item_id": 101, "name": "Access Token", "slot": 1},
+			{"item_id": 102, "name": "Comm Log", "slot": 2},
+		],
+		"entities": [
+			{"entity_id": 1, "x": 10.0, "y": 10.0, "z": 0, "kind": "Player",
+			 "visibility": "Forward", "relationship": "Unknown", "observation": "Visible"},
+		],
+		"visible_tiles": [
+			{"x": 10, "y": 10, "z": 0, "visibility": "Forward", "tile_kind": "Floor"},
+		],
+		"nearby_interactions": [{
+			"entity_id": 2,
+			"entity_type": "Npc",
+			"distance": 1,
+			"verbs": [{"kind": "Talk", "label": "Talk", "priority": 1, "available": true}],
+		}],
+		"current_monologue": {
+			"id": "test_001",
+			"text": "Sova Transit. The usual crowd.",
+			"duration_seconds": 4.0,
+		},
+	}
+	var encoded = Messagepack.encode(raw)
+	var snapshot = Protocol.decode_snapshot(encoded.value)
+
+	assert_that(snapshot).is_not_null()
+	assert_that(snapshot.tick).is_equal(100)
+	assert_that(snapshot.version).is_equal(Protocol.PROTOCOL_VERSION)
+	assert_that(snapshot.player_facing).is_equal("Southeast")
+	assert_that(snapshot.player_stance).is_equal("Careful")
+	assert_that(snapshot.player_inventory.size()).is_equal(3)
+	assert_that(snapshot.entities.size()).is_equal(1)
+	assert_that(snapshot.nearby_interactions.size()).is_equal(1)
+	assert_that(snapshot.current_monologue).is_not_null()
+	assert_that(snapshot.current_monologue.text).is_equal("Sova Transit. The usual crowd.")
+
+
+func test_full_v6_snapshot_to_game_state() -> void:
+	var snapshot := {
+		"tick": 50,
+		"player_stance": "Crouch",
+		"player_inventory": [
+			{"item_id": 200, "name": "Access Token", "slot": 4},
+		],
+		"entities": [
+			{"entity_id": 1, "x": 5.0, "y": 5.0, "z": 0, "kind": {"variant": "Player", "data": null}},
+		],
+	}
+	GameState.apply_snapshot(snapshot)
+
+	assert_that(GameState.current_tick).is_equal(50)
+	assert_that(GameState.player_stance).is_equal("Crouch")
+	assert_that(GameState.player_inventory.size()).is_equal(1)
+	assert_that(GameState.player_inventory[0].name).is_equal("Access Token")
+	assert_that(GameState.player_inventory[0].slot).is_equal(4)
+	assert_that(GameState.player_position).is_equal(Vector2(5, 5))
+
+	# Reset
+	GameState.player_stance = "Walk"
+	GameState.player_inventory = []

server/tests/serialization.rs

@@ -90,6 +90,9 @@ fn all_player_action_variants_roundtrip() {
         PlayerAction::UsePerceptionMode("thermal".to_string()),
         PlayerAction::Pause,
         PlayerAction::Unpause,
+        PlayerAction::SetTickRate(TickRate::Half),
+        PlayerAction::ToggleStanceUp,
+        PlayerAction::ToggleStanceDown,
     ];
 
     for action in actions {