Initial commit: Runware-powered content generator foundation

Laravel app with a cost-tracked Runware.ai integration (image, video,
text generation), a hard monthly EUR budget cap with live USD/EUR FX
conversion, and a locally-maintained model/pricing table since
Runware's model-search API doesn't expose pricing.

app/Exceptions/BudgetExceededException.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace App\Exceptions;
+
+use RuntimeException;
+
+class BudgetExceededException extends RuntimeException
+{
+    public function __construct(
+        public readonly float $spentEur,
+        public readonly float $capEur,
+        public readonly float $estimatedEur,
+    ) {
+        parent::__construct(sprintf(
+            'Runware monthly budget would be exceeded: %.2f€ spent + %.2f€ estimated > %.2f€ cap.',
+            $spentEur,
+            $estimatedEur,
+            $capEur,
+        ));
+    }
+}