ci: update workflows to use local-ubuntu-latest runner

Changed both CI and publish workflows to target local self-hosted
runner instead of GitHub-hosted ubuntu-latest.

Changes:
- .github/workflows/ci.yml: runs-on: local-ubuntu-latest
- .github/workflows/publish.yml: runs-on: local-ubuntu-latest

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: local-ubuntu-latest
 
     steps:
       - name: Checkout code

.github/workflows/publish.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   build-and-publish:
-    runs-on: ubuntu-latest
+    runs-on: local-ubuntu-latest
 
     steps:
       - name: Checkout code