chore: bump version to v0.1.15

Use toProperty + identifiers instead of fromProperty to resolve
application slug correctly.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config/version.yaml

@@ -1,2 +1,2 @@
 parameters:
-    app.version: '0.1.14'
+    app.version: '0.1.15'

src/Entity/Environment.php

@@ -21,7 +21,7 @@ use Symfony\Component\Serializer\Attribute\Groups;
         new Post(
             uriTemplate: '/applications/{slug}/environments',
             uriVariables: [
-                'slug' => new Link(fromClass: Application::class, fromProperty: 'environments'),
+                'slug' => new Link(toProperty: 'application', fromClass: Application::class, identifiers: ['slug']),
             ],
             security: "is_granted('ROLE_ADMIN')",
         ),