feat: implement player movement controller with grounded state, stair stepping, and wall interaction mechanics

characters/player/fps_camera_rig.gd

@@ -14,6 +14,7 @@ var _target_tilt: float = 0.0
 var _current_tilt: float = 0.0
 var _target_fov: float = 90.0
 var _weapon_fov_override: float = -1.0
+var _step_offset_y: float = 0.0
 
 
 func _ready() -> void:
@@ -80,6 +81,10 @@ func _process(delta: float) -> void:
 		camera.position.y = lerp(camera.position.y, 0.0, 0.15)
 		camera.position.x = lerp(camera.position.x, 0.0, 0.15)
 
+	# ── Step Smoothing ─────────────────────────────────────────────────────
+	_step_offset_y = lerpf(_step_offset_y, 0.0, 15.0 * delta)
+	camera.position.y += _step_offset_y
+
 	# ── Wall-run tilt ─────────────────────────────────────────────────────
 	_current_tilt = lerpf(_current_tilt, _target_tilt, 1.0 - exp(-params.wall_run_tilt_speed * delta))
 	camera.rotation.z = deg_to_rad(_current_tilt)
@@ -99,3 +104,9 @@ func set_weapon_fov(fov: float) -> void:
 ## Called to reset tilt (e.g., on landing).
 func clear_wall_tilt() -> void:
 	_target_tilt = 0.0
+
+## Adds an offset to the camera so that when the player physics body snaps up a step, 
+## the camera interpolates smoothly instead of snapping.
+func add_step_offset(offset_y: float) -> void:
+	_step_offset_y += offset_y
+