FEATURE: Add buildQuoteMarkdown for post toolbar (#24326)

This allows outlets for the post-text-selection-toolbar to
get just the raw markdown of the selected text for a quote,
rather than opening the composer.

app/assets/javascripts/discourse/app/components/post-text-selection-toolbar.gjs

@@ -235,6 +235,7 @@ export default class PostTextSelectionToolbar extends Component {
                 <PluginOutlet
                   @name="quote-share-buttons-after"
                   @connectorTagName="span"
+                  @outletArgs={{hash data=@data}}
                 />
               </span>
             </span>

app/assets/javascripts/discourse/app/components/post-text-selection.gjs

@@ -209,6 +209,7 @@ export default class PostTextSelection extends Component {
         topic: this.args.topic,
         quoteState,
         insertQuote: this.insertQuote,
+        buildQuote: this.buildQuote,
         hideToolbar: this.hideToolbar,
       },
     };
@@ -271,6 +272,11 @@ export default class PostTextSelection extends Component {
     await this.hideToolbar();
   }
 
+  @action
+  async buildQuote() {
+    return await this.args.buildQuoteMarkdown();
+  }
+
   <template>
     <div
       {{this.documentListeners}}

app/assets/javascripts/discourse/app/controllers/topic.js

@@ -457,6 +457,18 @@ export default Controller.extend(bufferedProperty("model"), {
       });
     },
 
+    buildQuoteMarkdown() {
+      const { postId, buffer, opts } = this.quoteState;
+      const loadedPost = this.get("model.postStream").findLoadedPost(postId);
+      const promise = loadedPost
+        ? Promise.resolve(loadedPost)
+        : this.get("model.postStream").loadPost(postId);
+
+      return promise.then((post) => {
+        return buildQuote(post, buffer, opts);
+      });
+    },
+
     fillGapBefore(args) {
       return this.get("model.postStream").fillGapBefore(args.post, args.gap);
     },

app/assets/javascripts/discourse/app/templates/topic.hbs

@@ -596,6 +596,7 @@
   <PostTextSelection
     @quoteState={{this.quoteState}}
     @selectText={{action "selectText"}}
+    @buildQuoteMarkdown={{this.buildQuoteMarkdown}}
     @editPost={{action "editPost"}}
     @topic={{this.model}}
   />