Open a TaskStream board when a project is created through the API

`taskstream: true` on POST /v1/projects also creates the project in
TaskStream, public, as the caller (their Pireon token is passed on), and
the answer carries `taskstream_key` and `taskstream_url`. The key is
`taskstream_key` or one made from the default-language slug.

The board is opened before the project is saved: if TaskStream refuses
it, nothing is created here and the reason comes back as a validation
error (502 when TaskStream does not answer). Machine tokens need the
server's own TASKSTREAM_TOKEN. Updates ignore the flag, and duplicates do
not inherit the link.

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

app/Http/Resources/ProjectResource.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Http\Resources;
 
 use App\Models\Project;
+use App\Services\TaskStream\TaskStreamClient;
 use App\Support\ImagePayload;
 use App\Support\TranslatablePayload;
 use Illuminate\Http\Request;
@@ -33,6 +34,10 @@ class ProjectResource extends JsonResource
             'is_featured' => (bool) $this->is_featured,
             'needs_help' => (bool) $this->needs_help,
             'demo_url' => $this->demo_url,
+            'taskstream_key' => $this->taskstream_key,
+            'taskstream_url' => $this->taskstream_key !== null
+                ? app(TaskStreamClient::class)->projectUrl($this->taskstream_key)
+                : null,
             // The stored path, which is what a client PATCHes back; what was
             // derived from it travels alongside, as on a page.
             'cover_image' => $this->cover_image,