NEON-29: Ledge peel via position — GROUNDED eats vy on floor

CharacterBody3D MOTION_MODE_GROUNDED move_and_slide clears downward
velocity while is_on_floor(), so gravity on velocity never produced
vertical motion off terrace lips (all prior probe/snap tweaks were no-ops).

After each walk move_and_slide, when the goal surface is below the feet
and probes/deep-descent say drop, accumulate peel_vy += g·dt and apply
global_position.y += peel_vy·dt. Airborne walk still uses velocity gravity.

Set physics/3d/default_gravity=9.81 explicitly in project.godot.

client/project.godot

@@ -67,6 +67,7 @@ dev_toggle_occluder_obstacle={
 [physics]
 
 common/physics_ticks_per_second=120
+3d/default_gravity=9.81
 3d/physics_engine="Jolt Physics"
 
 [rendering]

client/scripts/player.gd

@@ -126,6 +126,9 @@ var _debug_trace_frame: int = 0
 var _walk_nav_column_steering: bool = false
 ## Schmitt latch for vertical routing (see [member WALK_VERT_ROUTE_LATCH_ON_SEP]).
 var _walk_vert_route_latched: bool = false
+## GROUNDED [method move_and_slide] clears downward [code]velocity.y[/code] on floor; accumulate peel
+## speed here and apply [code]global_position.y[/code] so terrace lips can actually drop.
+var _walk_ledge_peel_vy: float = 0.0
 @onready var _nav_agent: NavigationAgent3D = $NavigationAgent3D
 
 
@@ -150,11 +153,13 @@ func set_authoritative_nav_goal(world_pos: Vector3) -> void:
 	_idle_stable_enter_streak = 0
 	_walk_nav_column_steering = false
 	_walk_vert_route_latched = false
+	_walk_ledge_peel_vy = 0.0
 	_nav_agent.set_target_position(world_pos)
 
 
 func clear_nav_goal() -> void:
 	velocity = Vector3.ZERO
+	_walk_ledge_peel_vy = 0.0
 	_has_walk_goal = false
 	_floor_angle_loose_ticks = FLOOR_ANGLE_LOOSE_TICKS_AFTER_STOP
 	_step_assist_active = false
@@ -195,6 +200,7 @@ func snap_to_server(world_pos: Vector3) -> void:
 	global_position = settled
 	velocity = Vector3.ZERO
 	_has_walk_goal = false
+	_walk_ledge_peel_vy = 0.0
 	# Force corrective idle ticks so Jolt resolves any residual physics state before walking.
 	_floor_angle_loose_ticks = FLOOR_ANGLE_LOOSE_TICKS_AFTER_STOP
 	_step_assist_cooldown = 0
@@ -443,30 +449,40 @@ func _walk_has_close_floor_probe_below(move_dir_xz: Vector2) -> bool:
 ## toward a floor click and poisons horizontal motion / slide resolution.
 ## Do apply gravity when [code]is_on_floor()[/code] is still true but there is no walkable surface
 ## within [member WALK_SUPPORT_PROBE_DEPTH] under the foot disk (ledge / void while moving).
-## [param feet_y] is [method capsule_feet_y] for the current body origin (see [member CAPSULE_HALF_HEIGHT]).
-## [param move_dir_xz] steers multi-sample rays (see [method _walk_probe_xz_offsets]).
-func _apply_walk_air_gravity(
-	delta: float, feet_y: float, move_dir_xz: Vector2 = Vector2.ZERO
-) -> void:
-	var apply_gravity: bool = not is_on_floor()
-	if (
-		not apply_gravity
-		and _has_walk_goal
-		and is_on_floor()
-		and not _walk_has_close_floor_probe_below(move_dir_xz)
-	):
-		apply_gravity = true
-	if (
-		not apply_gravity
-		and _has_walk_goal
-		and is_on_floor()
-		and feet_y > _auth_walk_goal.y + WALK_DEEP_DESCENT_FEET_ABOVE_GOAL
-	):
-		apply_gravity = true
-	if apply_gravity:
+## Only while **airborne**. With default [member MotionMode.MOTION_MODE_GROUNDED], [method move_and_slide]
+## clears downward [code]velocity.y[/code] every tick while [method is_on_floor] — adding gravity on the
+## velocity does **not** move the body off a terrace lip; use [method _apply_walk_post_slide_ledge_peel].
+func _apply_walk_air_gravity(delta: float, _feet_y: float, _move_dir_xz: Vector2 = Vector2.ZERO) -> void:
+	if not is_on_floor():
 		velocity += get_gravity() * delta
 
 
+## After [method move_and_slide], peel the capsule down when the authoritative goal is below the feet
+## but the engine still reports floor contact (GROUNDED mode ate negative [code]velocity.y[/code]).
+## Uses a small accumulated peel speed so displacement matches [code]∫ g dt[/code], not [code]g Δt[/code] (wrong units).
+func _apply_walk_post_slide_ledge_peel(
+	delta: float, feet_y: float, move_dir_xz: Vector2
+) -> void:
+	if not _has_walk_goal:
+		_walk_ledge_peel_vy = 0.0
+		return
+	if not is_on_floor():
+		_walk_ledge_peel_vy = 0.0
+		return
+	if _auth_walk_goal.y >= feet_y - DESCEND_GOAL_Y_MARGIN:
+		_walk_ledge_peel_vy = 0.0
+		return
+	var peel: bool = (
+		feet_y > _auth_walk_goal.y + WALK_DEEP_DESCENT_FEET_ABOVE_GOAL
+		or not _walk_has_close_floor_probe_below(move_dir_xz)
+	)
+	if not peel:
+		_walk_ledge_peel_vy = 0.0
+		return
+	_walk_ledge_peel_vy += get_gravity().y * delta
+	global_position.y += _walk_ledge_peel_vy * delta
+
+
 func _walk_floor_snap_length(
 	feet_y: float, want_goal_h: Vector3, move_dir_xz: Vector2 = Vector2.ZERO
 ) -> float:
@@ -938,6 +954,7 @@ func _physics_process(delta: float) -> void:
 	if horiz_dist <= ARRIVE_EPS and vert_err <= VERT_ARRIVE_EPS:
 		velocity = Vector3.ZERO
 		_has_walk_goal = false
+		_walk_ledge_peel_vy = 0.0
 		floor_block_on_wall = true
 		_floor_angle_loose_ticks = FLOOR_ANGLE_LOOSE_TICKS_AFTER_STOP
 		_step_assist_active = false
@@ -1003,6 +1020,10 @@ func _physics_process(delta: float) -> void:
 	_apply_walk_air_gravity(delta, feet_y, walk_move_dir_xz)
 	floor_snap_length = _walk_floor_snap_length(feet_y, want_goal_h, walk_move_dir_xz)
 	move_and_slide()
+	var feet_after: float = capsule_feet_y(
+		global_position.y, CAPSULE_HALF_HEIGHT + PLAYER_CAPSULE_RADIUS
+	)
+	_apply_walk_post_slide_ledge_peel(delta, feet_after, walk_move_dir_xz)
 	_after_walk_move_and_slide()
 	_clear_step_assist_after_walk_move()
 	_debug_trace_transform("physics")