ci: run the test job on pushes to master (#10054)

The Code Test workflow only has a pull_request trigger, so the suite
never runs against master itself: a direct push is untested, and a
merge can break tests even when the pull request's own check was
green, because checks run on the PR head rather than on the merged
result. Add a push trigger for master with the same paths filter.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/test.yml

@@ -1,6 +1,17 @@
 name: Code Test
 
 on:
+  push:
+    branches:
+      - master
+    paths:
+      - 'v2rayN/ServiceLib/**'
+      - 'v2rayN/ServiceLib.UdpTest/**'
+      - 'v2rayN/ServiceLib.Tests/**'
+      - 'v2rayN/Directory.Build.*'
+      - 'v2rayN/Directory.Packages.props'
+      - 'global.json'
+      - '.github/workflows/test.yml'
   pull_request:
     branches:
       - master