Merge pull request 'ci: switch to ubuntu-latest now that repo is public' (#4) from fix/ci-use-ubuntu-latest into main

.github/workflows/ci.yml

@@ -6,12 +6,7 @@ on:
     branches: [main]
 jobs:
   build:
-    # Self-hosted Mac mini — this repo is private and the org's
-    # GitHub-hosted minute budget is exhausted (every ubuntu-latest job
-    # dies in 2s with no step output). Per the 2026-04-22 carve-out:
-    # private repos run on self-hosted; public repos use ubuntu-latest
-    # (still free).
-    runs-on: self-hosted
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4