Redirect legacy /q/* URLs to canonical ladl.link addresses.

External /q requests 301/307 to ladl.link; internal X-Ladill-Internal requests still serve content for platform proxying.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/Feature/LinkRedirectTest.php

@@ -59,5 +59,10 @@ class LinkRedirectTest extends TestCase
         $this->get('https://ladl.link/qrpage')
             ->assertOk()
             ->assertSee('QR page');
+
+        Http::assertSent(function ($request) {
+            return $request->url() === 'https://ladill.com/q/qrpage'
+                && $request->hasHeader('X-Ladill-Internal', '1');
+        });
     }
 }