Wolves with a den, fishing, and a mixed diet

Wolves
- Den: a boulder cave at the foot of the rim, sited from the seed (away
  from the sea and spawn, mouth toward the valley, clearing in front)
- Grace period: no wolves days 1-2; they move in on day 3 and howl; hunting
  from night 4; pack of 2, 3 from day 6, 4 from day 9; replaced by day
- Wary pack hunters: circle and dart in one at a time; a lit campfire is a
  safe zone, a torch makes them hesitate, walls block bites (line of
  sight); hit one and the pack turns; hurt wolves flee; a lone wolf is
  timid; by day they defend the den; home at dawn
- Glowing eyes, synthesised howls, can't sleep with wolves prowling
- Wolf pelt and Wolf Cloak (+25 warmth)
- Animals take a committed detour around obstacles

Fishing
- Fishing rod (workbench); cast a float onto the lake, 1.5 s to land a bite
- Perch and rarer trout; faster bites at dawn/dusk and in rain; grill them
- Visible fish near the shore that jump with splash rings

Mixed diet
- Foods belong to meat, fish or greens; each level runs down over ~1.5 days
- One group low: no healing; two low: Malnourished (health drains);
  all three good: Balanced diet (heal x1.5); HUD diet bars; saved

Tests: test_wolves and test_fishing_diet; run_all.sh covers 9 suites

scripts/world/props.gd

@@ -759,12 +759,17 @@ func _make_grass_tile(k: Vector2i) -> Node3D:
 ## half width]. Set by world.gd whenever floors are built or removed; only the
 ## grass tiles around old and new floors are rebuilt.
 var _grass_cuts: Array = []
+## Permanent cuts (the wolf den floor): [transform, half width x, half depth z].
+var static_cuts: Array = []
 
 func set_grass_cuts(xforms: Array, half: float) -> void:
 	var old := _grass_cuts
 	_grass_cuts = []
 	for xf: Transform3D in xforms:
-		_grass_cuts.append([xf.affine_inverse(), xf.origin, half])
+		_grass_cuts.append([xf.affine_inverse(), xf.origin, half, half])
+	for c in static_cuts:
+		var xf: Transform3D = c[0]
+		_grass_cuts.append([xf.affine_inverse(), xf.origin, float(c[1]), float(c[2])])
 	var touched := {}
 	for c in old + _grass_cuts:
 		var p: Vector3 = c[1]
@@ -783,7 +788,7 @@ func set_grass_cuts(xforms: Array, half: float) -> void:
 static func _under_cut(cuts: Array, x: float, z: float) -> bool:
 	for c in cuts:
 		var l: Vector3 = (c[0] as Transform3D) * Vector3(x, (c[1] as Vector3).y, z)
-		if absf(l.x) < c[2] and absf(l.z) < c[2]:
+		if absf(l.x) < c[2] and absf(l.z) < c[3]:
 			return true
 	return false