Use ubuntu-slim runner for lightweight workflow jobs

- Switch labeler, spellcheck, publish and the test lint job to ubuntu-slim
- Keep ubuntu-latest for Docker-based actions, CodeQL, the OS/Node test matrix and the website build

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B4uAX78vP2cYisKwLmZgSP

Author: claude

.github/workflows/labeler.yml

@@ -12,7 +12,7 @@ jobs:
     permissions:
       contents: read # for actions/labeler to determine modified files
       pull-requests: write # for actions/labeler to add labels to PRs
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - uses: actions/labeler@bf12e9b00b37c5c0ca2b87b79b2daf7891dbda13 # v7.0.0
         with:

.github/workflows/publish.yml

@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: ⬇️ Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

.github/workflows/spellcheck.yml

@@ -15,7 +15,7 @@ permissions:
 
 jobs:
   spellcheck:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     if: ${{ github.actor != 'dependabot[bot]' }}
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

.github/workflows/test.yml

@@ -15,7 +15,7 @@ permissions:
 
 jobs:
   lint:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: ⬇️ Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1