M1b: survival stats, day/night, fire fuel, cooking, foraging, torches, death + grave

- Health, stamina, hunger, warmth and wet with HUD bars, status tags and clock
- 20-minute day/night cycle with moon, stars and lit clouds
- Campfire fuel (2 min start, 15 min max), heat radius, cooking needs a lit fire
- Berry bushes (regrow 10 min), mushrooms, roasted mushroom, torch
- Stamina costs for sprint, jump and harvest hits
- Death respawns at island start and leaves a grave bag
- Saves include stats, time of day, fire fuel, regrowth timers and graves
- New test_survival_stats suite; tests fail if a script error aborts them

scripts/player/player.gd

@@ -26,6 +26,7 @@ var inventory := Inventory.new(40)   ## slots 0-7 are the hotbar
 var selected := 0
 var ui_open := false                 ## set by the inventory screen; freezes look/move
 var hands: Node3D
+var survival: Node                   ## health / stamina / hunger / warmth (survival.gd)
 
 var _gravity: float = ProjectSettings.get_setting("physics/3d/default_gravity", 9.8)
 
@@ -36,6 +37,11 @@ func _ready() -> void:
 	hands.name = "Hands"
 	hands.player = self
 	camera.add_child(hands)
+	survival = preload("res://scripts/player/survival.gd").new()
+	survival.name = "Survival"
+	survival.player = self
+	survival.world = get_parent()
+	add_child(survival)
 
 func held_item_id() -> String:
 	var s = inventory.get_slot(selected)
@@ -70,17 +76,21 @@ func _physics_process(delta: float) -> void:
 	elif not is_on_floor():
 		velocity.y -= _gravity * delta
 
+	if global_position.y < water_level - 0.6:
+		survival.soak()   # waist-deep or more: you're wet
+
 	var jump := Input.is_action_just_pressed("jump") and not ui_open
-	if jump and is_on_floor():
-		velocity.y = jump_velocity
-	elif 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.
+	var can_swim_jump := global_position.y > float_y - 0.4 and global_position.y < float_y + 0.3
+	if jump and (is_on_floor() or can_swim_jump) and survival.use_stamina(8.0):
+		# (A swim-jump kicks you up out of the water onto a bank.)
 		velocity.y = jump_velocity
 
 	var input_dir := Vector2.ZERO if ui_open else 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
+	var sprinting: bool = Input.is_key_pressed(KEY_SHIFT) and direction.length() > 0.1 and not ui_open \
+		and survival.use_stamina(14.0 * delta, true)
+	var current_speed := sprint_speed if sprinting else speed
 	if swimming:
 		current_speed = swim_speed
 	if direction: