feat: fix duplicate CI runs on pull requests (#83)

* Initial plan

* Fix CI duplicate checks by restricting push triggers to master branch

Co-authored-by: hsluoyz <3787410+hsluoyz@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: hsluoyz <3787410+hsluoyz@users.noreply.github.com>

Author: Copilot

.github/workflows/main.yml

@@ -1,5 +1,9 @@
 name: main
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - master
 jobs:
   test:
     runs-on: ubuntu-latest