M0.5: detailed scenery, mountain/sea-cliff boundary, Godot 4.7

Scenery (all procedural, seeded, no imported assets):
- Terrain shader: grass/dry grass/dirt/sand/rock strata/snow + detail normals
- 5 tree types, faceted mossy rocks, cliff outcrops, sea stacks, bushes,
  logs and stumps, batched as MultiMesh per 48 m cell
- Wind-animated grass and flowers streamed in tiles around the player
- Lake (depth-shaded water with shore foam), ocean to the horizon,
  cloud sky shader, volumetric fog, glow, softer shadows
- Swimming: float at the surface, swim-jump to climb out

World bounds:
- Steep mountain rim with an invisible wall partway up; one side opens to
  a sheer sea cliff with the wall 1 m inside the edge; whole chunk is an
  island so the mesh edge is never visible
- Respawn safety net if the player leaves the walkable area or the map
- Fix: the cliff edge now tracks the wall in the headlands (it used to
  drop away inside the wall, leaving a pit with lake water hanging over it)

Tests: tests/test_boundary.gd (24-direction escape attempt) and
tests/test_terrain_edges.gd (no ground below waterline near the wall).

Upgrades the project to Godot 4.7 (project.godot rewritten by the 4.7
importer, .uid files added) and documents it in the setup guide.

scripts/player/player.gd

@@ -1,14 +1,20 @@
 extends CharacterBody3D
-## First-person player controller — M0.
+## First-person player controller.
 ##
-## Move (WASD), look (mouse), jump (space). Gravity + ground collision via
-## CharacterBody3D. Deliberately minimal: no stamina/health yet (M1), no network
-## ownership yet (M2). Press ESC to free the mouse, click to recapture.
+## Move (WASD), look (mouse), jump (space), sprint (shift). Gravity + ground
+## collision via CharacterBody3D. In deep water the player floats with their
+## head above the surface and moves at swimming speed. Deliberately minimal: no
+## stamina/health yet (M1), no network ownership yet (M2). Press ESC to free the
+## mouse, click to recapture.
 
 @export var speed: float = 5.0
 @export var sprint_speed: float = 8.0
+@export var swim_speed: float = 2.6
 @export var jump_velocity: float = 5.5
 @export var mouse_sensitivity: float = 0.0025
+## Set by world.gd from the terrain. Feet this far below the surface = swimming.
+@export var water_level: float = -INF
+const FLOAT_DEPTH := 1.3
 
 @onready var camera: Camera3D = $Camera3D
 
@@ -28,16 +34,27 @@ func _unhandled_input(event: InputEvent) -> void:
 		Input.mouse_mode = Input.MOUSE_MODE_CAPTURED
 
 func _physics_process(delta: float) -> void:
-	if not is_on_floor():
+	var float_y := water_level - FLOAT_DEPTH
+	var swimming := global_position.y < float_y + 0.05 and not is_on_floor()
+
+	if global_position.y < float_y:
+		# Buoyancy: ease back up to floating height.
+		velocity.y = move_toward(velocity.y, clampf((float_y - global_position.y) * 4.0, -3.0, 3.0), 20.0 * delta)
+	elif not is_on_floor():
 		velocity.y -= _gravity * delta
 
 	if Input.is_action_just_pressed("jump") and is_on_floor():
 		velocity.y = jump_velocity
+	elif Input.is_action_just_pressed("jump") and global_position.y > float_y - 0.4 and global_position.y < float_y + 0.3:
+		# Swim-jump: kick up out of the water to climb onto a bank.
+		velocity.y = jump_velocity
 
 	var input_dir := Input.get_vector("move_left", "move_right", "move_forward", "move_back")
 	var direction := (transform.basis * Vector3(input_dir.x, 0, input_dir.y)).normalized()
 
 	var current_speed := sprint_speed if Input.is_key_pressed(KEY_SHIFT) else speed
+	if swimming:
+		current_speed = swim_speed
 	if direction:
 		velocity.x = direction.x * current_speed
 		velocity.z = direction.z * current_speed

scripts/player/player.gd.uid

@@ -0,0 +1 @@
+uid://dbsqgv3wwo41p