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

docs/SETUP_ON_NEW_MACHINE.md

@@ -23,6 +23,8 @@ godot --headless --path . --script res://tests/test_terrain_edges.gd
 godot --headless --path . --script res://tests/test_survival_core.gd
 # Save/load round trip + world slots (uses user://test_worlds, not your saves)
 godot --headless --path . --script res://tests/test_save_load.gd
+# Survival stats: hunger, warmth, fire fuel, cooking, foraging, death + grave
+godot --headless --path . --script res://tests/test_survival_stats.gd
 ```
 
 ## Save files