test: use wait-for-hydra SSE endpoint for real-time status

Switch pr-validate workflow to use the SSE-enabled wait-for-hydra
action branch. This connects to ci.zw3rk.com's SSE endpoint for
instant build status updates instead of polling the GitHub API.

Test PR — do not merge.

Author: angerman

.github/workflows/pr-validate.yml

@@ -15,9 +15,10 @@ jobs:
     name: Wait for Hydra status
     runs-on: ubuntu-latest
     steps:
-    - uses: input-output-hk/actions/wait-for-hydra@latest
+    - uses: input-output-hk/actions/wait-for-hydra@wait-for-hydra/sse-support
       with:
         check: required
+        hydra-status-url: https://ci.zw3rk.com
 
   discover:
     needs: wait-for-hydra