feat(gameplay): consommables utilisables avec touche [F]

- DolphinController expose heal/feed/refill_oxygen + signal
  use_consumable_requested (bindé sur F)
- Main.gd table CONSUMABLE_EFFECTS:
  · Bulle d'air (102): +40 O₂
  · Algue cuisinée (103): +30 faim, +5 HP
  · Amulette de soin (106): +50 HP
- Popup flottant coloré au-dessus du joueur + son bulle à l'utilisation
- HUD: hint dynamique "[F] Consommer : <item>" quand slot sélectionné = consommable

Boucle court-terme: le craft a enfin un usage direct, récompense lisible.

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

scripts/dolphin/DolphinController.gd

@@ -18,6 +18,7 @@ signal hotbar_scroll(direction: int)
 signal echolocation_triggered(position: Vector3, radius: float)
 signal stats_changed(oxygen: float, health: float, hunger: float)
 signal player_died()
+signal use_consumable_requested()
 
 # --- Internal State ---
 var oxygen: float
@@ -61,6 +62,7 @@ func _setup_input_actions() -> void:
 		"boost": KEY_CTRL,
 		"echolocate": KEY_E,
 		"toggle_inventory": KEY_TAB,
+		"use_consumable": KEY_F,
 	}
 	for action_name: String in actions:
 		if not InputMap.has_action(action_name):
@@ -103,6 +105,8 @@ func _input(event: InputEvent) -> void:
 		_do_raycast_place()
 	if event.is_action_pressed("echolocate"):
 		_trigger_echolocation()
+	if event.is_action_pressed("use_consumable"):
+		use_consumable_requested.emit()
 
 
 func _physics_process(delta: float) -> void:
@@ -264,6 +268,21 @@ func take_damage(amount: float) -> void:
 		player_died.emit()
 
 
+func heal(amount: float) -> void:
+	health = min(max_health, health + amount)
+	_emit_stats()
+
+
+func feed(amount: float) -> void:
+	hunger = min(max_hunger, hunger + amount)
+	_emit_stats()
+
+
+func refill_oxygen(amount: float) -> void:
+	oxygen = min(max_oxygen, oxygen + amount)
+	_emit_stats()
+
+
 func _trigger_echolocation() -> void:
 	if is_echolocating:
 		return