Point the public site to each project's TaskStream board

A project with a board now carries its key, its address and the address
of the board's public showcase in the public API, so the website can show
its roadmap, releases and tickets for newcomers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Services/TaskStream/TaskStreamClient.php

@@ -85,4 +85,21 @@ class TaskStreamClient
     {
         return "{$this->webUrl}/p/{$key}";
     }
+
+    /**
+     * The public summary of a board (roadmap, releases, sprint, tickets for
+     * newcomers). Anyone may read it, so the public site can ask directly.
+     */
+    public function showcaseUrl(string $key): string
+    {
+        return "{$this->apiUrl}/api/explore/projects/{$key}/showcase";
+    }
+
+    /**
+     * Where the paths of a showcase (`/p/KEY/issues/KEY-3`) are opened.
+     */
+    public function webUrl(): string
+    {
+        return $this->webUrl;
+    }
 }