Refactor outfit-layer component to use internal state API, not attrs

Oh right okay, attributes like `status="loading"` are more of an API
for the caller, whereas the internal state API is where you wanna put
things that are meant to be used in CSS selectors and stuff.

app/assets/javascripts/outfit-viewer.js

@@ -1,4 +1,11 @@
 class OutfitLayer extends HTMLElement {
+	#internals;
+
+	constructor() {
+		super();
+		this.#internals = this.attachInternals();
+	}
+
 	connectedCallback() {
 		setTimeout(() => this.#initializeImage(), 0);
 	}
@@ -16,7 +23,8 @@ class OutfitLayer extends HTMLElement {
 	}
 
 	#setStatus(newStatus) {
-		this.setAttribute("status", newStatus);
+		this.#internals.states.clear();
+		this.#internals.states.add(newStatus);
 	}
 }
 

app/assets/stylesheets/items/_show.sass

@@ -58,7 +58,7 @@ body.items-show
         width: 100%
         height: 100%
 
-    &:has(outfit-layer[status="loading"])
+    &:has(outfit-layer:state(loading))
       background: gray
 
   .species-color-picker