feat(hud): compass + depth + biome indicator

Panneau info top-right avec boussole (8 directions FR), profondeur
en mètres depuis la surface, et nom de biome courant (Récif Corallien,
Forêt de Kelp, Plateau Rocheux, Abysses). Helper biome_name_at dans
WorldGenerator pour requête client-side sans relire les chunks.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/dolphin/HUD.gd

@@ -1,14 +1,75 @@
 extends CanvasLayer
 
+const WATER_SURFACE_Y: float = 60.0
+
 @onready var _oxygen_bar: ProgressBar = %OxygenBar
 @onready var _health_bar: ProgressBar = %HealthBar
 @onready var _hunger_bar: ProgressBar = %HungerBar
 
+var _dolphin: Node3D = null
+var _world_seed: int = 12345
+
+var _info_panel: PanelContainer = null
+var _depth_label: Label = null
+var _biome_label: Label = null
+var _compass_label: Label = null
+
+var _biome_cache_pos: Vector3 = Vector3(99999, 99999, 99999)
+var _biome_cached_name: String = ""
+
 
 func _ready() -> void:
 	_style_bar(_oxygen_bar, Color(0.31, 0.76, 0.97))
 	_style_bar(_health_bar, Color(0.91, 0.30, 0.24))
 	_style_bar(_hunger_bar, Color(0.95, 0.61, 0.07))
+	_build_info_panel()
+
+
+func _build_info_panel() -> void:
+	_info_panel = PanelContainer.new()
+	_info_panel.anchor_left = 1.0
+	_info_panel.anchor_right = 1.0
+	_info_panel.anchor_top = 0.0
+	_info_panel.anchor_bottom = 0.0
+	_info_panel.offset_left = -220.0
+	_info_panel.offset_top = 16.0
+	_info_panel.offset_right = -16.0
+	_info_panel.offset_bottom = 112.0
+
+	var style := StyleBoxFlat.new()
+	style.bg_color = Color(0.05, 0.05, 0.05, 0.7)
+	style.corner_radius_top_left = 10
+	style.corner_radius_top_right = 10
+	style.corner_radius_bottom_left = 10
+	style.corner_radius_bottom_right = 10
+	_info_panel.add_theme_stylebox_override("panel", style)
+
+	var vbox := VBoxContainer.new()
+	vbox.add_theme_constant_override("separation", 4)
+	_info_panel.add_child(vbox)
+
+	_compass_label = Label.new()
+	_compass_label.text = "⬆ N"
+	_compass_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	_compass_label.add_theme_font_size_override("font_size", 20)
+	_compass_label.add_theme_color_override("font_color", Color(0.85, 0.95, 1.0))
+	vbox.add_child(_compass_label)
+
+	_depth_label = Label.new()
+	_depth_label.text = "Prof. 0 m"
+	_depth_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	_depth_label.add_theme_font_size_override("font_size", 14)
+	_depth_label.add_theme_color_override("font_color", Color(0.70, 0.88, 1.0))
+	vbox.add_child(_depth_label)
+
+	_biome_label = Label.new()
+	_biome_label.text = "Biome : —"
+	_biome_label.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	_biome_label.add_theme_font_size_override("font_size", 14)
+	_biome_label.add_theme_color_override("font_color", Color(0.85, 0.95, 0.75))
+	vbox.add_child(_biome_label)
+
+	add_child(_info_panel)
 
 
 func _style_bar(bar: ProgressBar, color: Color) -> void:
@@ -31,9 +92,55 @@ func _style_bar(bar: ProgressBar, color: Color) -> void:
 
 func connect_to_dolphin(dolphin: CharacterBody3D) -> void:
 	dolphin.stats_changed.connect(_on_stats_changed)
+	_dolphin = dolphin
+
+	var main: Node = get_tree().get_first_node_in_group("main")
+	if main != null:
+		var cm: Node = main.get_node_or_null("World/ChunkManager")
+		if cm != null and cm.get("world_seed") != null:
+			_world_seed = cm.world_seed
 
 
 func _on_stats_changed(oxygen: float, hp: float, hunger: float) -> void:
 	_oxygen_bar.value = oxygen
 	_health_bar.value = hp
 	_hunger_bar.value = hunger
+
+
+func _process(_delta: float) -> void:
+	if not is_instance_valid(_dolphin):
+		return
+
+	var depth_m: int = int(round(WATER_SURFACE_Y - _dolphin.global_position.y))
+	if _depth_label != null:
+		_depth_label.text = "Prof. %d m" % depth_m
+
+	if _compass_label != null:
+		_compass_label.text = _compass_text(_dolphin.rotation.y)
+
+	if _biome_label != null:
+		_update_biome_label()
+
+
+func _compass_text(yaw: float) -> String:
+	# Player forward is -Z when yaw=0 → North. Yaw rotates counterclockwise in Godot.
+	# Convert yaw to a heading [0, 360) where 0 = North, 90 = East.
+	var heading: float = rad_to_deg(-yaw)
+	heading = fposmod(heading, 360.0)
+
+	var labels: PackedStringArray = PackedStringArray(["N", "NE", "E", "SE", "S", "SO", "O", "NO"])
+	var arrows: PackedStringArray = PackedStringArray([
+		"⬆", "⬈", "➡", "⬊", "⬇", "⬋", "⬅", "⬉"
+	])
+	var idx: int = int(round(heading / 45.0)) % 8
+	return "%s %s" % [arrows[idx], labels[idx]]
+
+
+func _update_biome_label() -> void:
+	var pos: Vector3 = _dolphin.global_position
+	if pos.distance_to(_biome_cache_pos) < 4.0 and _biome_cached_name != "":
+		_biome_label.text = "Biome : %s" % _biome_cached_name
+		return
+	_biome_cache_pos = pos
+	_biome_cached_name = WorldGenerator.biome_name_at(pos.x, pos.z, pos.y, _world_seed)
+	_biome_label.text = "Biome : %s" % _biome_cached_name