ci: run push builds only on dtq

dtq-dev no longer exists, and we only care about dtq for now. PRs still
trigger via the pull_request event.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: jm

.github/workflows/tests.yml

@@ -2,7 +2,7 @@ name: Tests
 
 on:
   push:
-    branches: [ dtq, dtq-dev, main ]
+    branches: [ dtq ]
   pull_request:
 
 permissions: