Make gamepad vibration work on web export

Input.start_joy_vibration() is a documented engine no-op on Godot's
HTML5 export (never wired to the browser side). Controls.vibrate()
wraps it: native platforms go straight through as before, web drives
the browser's Gamepad Haptic Actuator API directly via JavaScriptBridge.
Gamepad movement/ability input already worked on desktop browsers via
the standard Web Gamepad API, so only vibration needed a fix.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MXBNaEBmrYDSMcv4NgUWtV

levels/lobby_underground.gd

@@ -11,5 +11,4 @@ func _process(_delta: float) -> void:
 	if Run.bear_gate_open() or DP.b("gate_unlocked_bear"):
 		bear_gate_open = true
 		$AnimationPlayer.play("Gate_opening")
-		if DP.b("gamepad_vibration"):
-			Input.start_joy_vibration(0, 0.5, .5, 7)
+		Controls.vibrate(0, 0.5, .5, 7)