Shards damage barefoot users + steptrigger-related general cleanup (#9585)

Content.Shared/StepTrigger/Systems/ShoesRequiredStepTriggerSystem.cs

@@ -0,0 +1,33 @@
+using Content.Shared.Examine;
+using Content.Shared.Inventory;
+using Content.Shared.StepTrigger.Components;
+
+namespace Content.Shared.StepTrigger.Systems;
+
+public sealed class ShoesRequiredStepTriggerSystem : EntitySystem
+{
+    [Dependency] private readonly InventorySystem _inventory = default!;
+
+    /// <inheritdoc/>
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<ShoesRequiredStepTriggerComponent, StepTriggerAttemptEvent>(OnStepTriggerAttempt);
+        SubscribeLocalEvent<ShoesRequiredStepTriggerComponent, ExaminedEvent>(OnExamined);
+    }
+
+    private void OnStepTriggerAttempt(EntityUid uid, ShoesRequiredStepTriggerComponent component, ref StepTriggerAttemptEvent args)
+    {
+        if (!TryComp<InventoryComponent>(args.Tripper, out var inventory))
+            return;
+
+        if (_inventory.TryGetSlotEntity(args.Tripper, "shoes", out _, inventory))
+        {
+            args.Cancelled = true;
+        }
+    }
+
+    private void OnExamined(EntityUid uid, ShoesRequiredStepTriggerComponent component, ExaminedEvent args)
+    {
+        args.PushMarkup(Loc.GetString("shoes-required-step-trigger-examine"));
+    }
+}