gmp(M02): extract local player movement

Work-Package: M02-GMP-MOVEMENT-001
Agent: sindo-main-codex
Tests: local movement and player input regressions; asset-free scene; renderer dry-run; coordinate, streaming, documentation and coordination gates
Fidelity: preserves current sandbox speed, acceleration, sprint and camera-relative flight behavior; build-12340 parity remains unverified

src/gameplay/movement/local_player_movement_controller.gd

@@ -0,0 +1,97 @@
+class_name LocalPlayerMovementController
+extends RefCounted
+
+## Scene-free state and velocity integrator for the current local sandbox player.
+## Direction inputs use a Godot-world movement basis selected by the scene
+## adapter. This class does not discover Nodes, query terrain or mutate transforms.
+
+var godot_world_velocity_units_per_second: Vector3:
+	get:
+		return _godot_world_velocity_units_per_second
+
+var is_flight_enabled: bool:
+	get:
+		return _is_flight_enabled
+
+var _run_speed_units_per_second: float
+var _backward_speed_units_per_second: float
+var _strafe_speed_units_per_second: float
+var _flight_vertical_speed_units_per_second: float
+var _acceleration_units_per_second_squared: float
+var _sandbox_sprint_multiplier: float
+var _godot_world_velocity_units_per_second := Vector3.ZERO
+var _is_flight_enabled := false
+
+
+## Creates a movement state with explicit Godot-unit speeds and acceleration.
+## The current compatibility renderer treats one Godot unit as one WoW yard.
+func _init(
+		run_speed_units_per_second: float,
+		backward_speed_units_per_second: float,
+		strafe_speed_units_per_second: float,
+		flight_vertical_speed_units_per_second: float,
+		acceleration_units_per_second_squared: float,
+		sandbox_sprint_multiplier: float
+) -> void:
+	_run_speed_units_per_second = run_speed_units_per_second
+	_backward_speed_units_per_second = backward_speed_units_per_second
+	_strafe_speed_units_per_second = strafe_speed_units_per_second
+	_flight_vertical_speed_units_per_second = flight_vertical_speed_units_per_second
+	_acceleration_units_per_second_squared = acceleration_units_per_second_squared
+	_sandbox_sprint_multiplier = sandbox_sprint_multiplier
+
+
+## Toggles sandbox free flight and clears velocity exactly like the pre-M02 controller.
+## Returns the new flight state.
+func toggle_sandbox_flight() -> bool:
+	_is_flight_enabled = not _is_flight_enabled
+	_godot_world_velocity_units_per_second = Vector3.ZERO
+	return _is_flight_enabled
+
+
+## Advances velocity by one physics step and returns local-world displacement.
+## `godot_world_movement_basis` is the player basis on ground and camera-pivot basis in flight.
+## Negative delta values are treated as zero and do not mutate velocity.
+func advance(
+		move_intent: MoveIntent,
+		godot_world_movement_basis: Basis,
+		delta_seconds: float
+) -> Vector3:
+	var safe_delta_seconds := maxf(delta_seconds, 0.0)
+	if is_zero_approx(safe_delta_seconds):
+		return Vector3.ZERO
+
+	var target_velocity := _calculate_target_velocity(move_intent, godot_world_movement_basis)
+	_godot_world_velocity_units_per_second = _godot_world_velocity_units_per_second.move_toward(
+		target_velocity,
+		_acceleration_units_per_second_squared * safe_delta_seconds
+	)
+	return _godot_world_velocity_units_per_second * safe_delta_seconds
+
+
+func _calculate_target_velocity(move_intent: MoveIntent, godot_world_movement_basis: Basis) -> Vector3:
+	var forward_direction := -godot_world_movement_basis.z
+	var right_direction := godot_world_movement_basis.x
+	if not _is_flight_enabled:
+		forward_direction.y = 0.0
+		right_direction.y = 0.0
+	forward_direction = forward_direction.normalized()
+	right_direction = right_direction.normalized()
+
+	var forward_speed := (
+		_run_speed_units_per_second
+		if move_intent.forward_axis > 0.0
+		else _backward_speed_units_per_second
+	)
+	var speed_multiplier := _sandbox_sprint_multiplier if move_intent.is_sprint_requested else 1.0
+	var target_velocity := (
+		forward_direction * move_intent.forward_axis * forward_speed
+		+ right_direction * move_intent.strafe_axis * _strafe_speed_units_per_second
+	) * speed_multiplier
+	if _is_flight_enabled:
+		target_velocity.y += (
+			move_intent.vertical_axis
+			* _flight_vertical_speed_units_per_second
+			* speed_multiplier
+		)
+	return target_velocity