[actions] Fix copilot-setup-steps workflow (#1390)

Fixes several issues with the `copilot-setup-steps` workflow:

- **Permission denied on /mnt**: Use `sudo mkdir` and `sudo chmod` to create build directories on the secondary disk
- **Broken symlinks**: Rename `externals-link`/`generated-link` to `externals`/`generated` so the build actually uses the secondary disk
- **Slow disk space logging**: Simplify `log-disk-space` action to just `df -h` — the `du` commands were scanning the entire filesystem (~1m45s per call)
- **PR trigger**: Add `pull_request` trigger so changes to the workflow are validated before merge

Author: jonathanpeppers

.github/workflows/copilot-setup-steps.yml

@@ -1,6 +1,10 @@
 name: "Copilot Setup Steps"
 
-on: workflow_dispatch
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
 
 jobs:
   copilot-setup-steps:
@@ -16,14 +20,15 @@ jobs:
     - name: Setup build directories on secondary disk
       run: |
         echo "Setting up build directories on /mnt (secondary disk with 66G+ free)"
-        mkdir -p /mnt/build-output
-        mkdir -p /mnt/externals
-        mkdir -p /mnt/generated
+        sudo mkdir -p /mnt/build-output
+        sudo mkdir -p /mnt/externals
+        sudo mkdir -p /mnt/generated
+        sudo chmod -R 777 /mnt/build-output /mnt/externals /mnt/generated
         
         # Create symlinks to use the secondary disk
         ln -s /mnt/build-output ./output
-        ln -s /mnt/externals ./externals-link
-        ln -s /mnt/generated ./generated-link
+        ln -s /mnt/externals ./externals
+        ln -s /mnt/generated ./generated
         
         echo "Build directories configured:"
         ls -la | grep -E "(output|externals|generated)"
@@ -70,17 +75,13 @@ jobs:
 
     - name: Log disk space (after externals cache restore)
       uses: ./.github/workflows/log-disk-space
-      with:
-        detailed: 'true'
 
     - name: Run dotnet cake
       run: dotnet cake
       continue-on-error: true
 
     - name: Log disk space (after dotnet cake)
       uses: ./.github/workflows/log-disk-space
-      with:
-        detailed: 'true'
 
     # Save the externals cache after dotnet cake runs
     # This ensures the cache reflects the original config.json state

.github/workflows/log-disk-space/action.yml

@@ -1,10 +1,5 @@
 name: Log Disk Space
 description: Logs disk space usage on the runner
-inputs:
-  detailed:
-    description: 'Whether to include detailed disk analysis (true/false)'
-    required: false
-    default: 'false'
 runs:
   using: composite
   steps:
@@ -13,48 +8,3 @@ runs:
     run: |
       echo "=== Disk Space Usage ==="
       df -h
-      echo ""
-      echo "=== Disk Usage by Directory (/) ==="
-      du -h -d 1 / 2>/dev/null | sort -hr | head -20 || true
-      echo ""
-      echo "=== Disk Usage in Current Directory ==="
-      du -h -d 1 . 2>/dev/null | sort -hr | head -20 || true
-      echo ""
-      echo "=== Disk Usage Summary ==="
-      df -h / | tail -1 | awk '{print "Used: " $3 " / " $2 " (" $5 " full)"}'
-      
-      # Detailed analysis if requested
-      if [ "${{ inputs.detailed }}" = "true" ]; then
-        echo ""
-        echo "=== DETAILED ANALYSIS ==="
-        echo ""
-        echo "=== Largest directories in /home/runner ==="
-        sudo du -h /home/runner 2>/dev/null | sort -rh | head -20
-        echo ""
-        echo "=== Largest directories in /opt ==="
-        sudo du -h /opt 2>/dev/null | sort -rh | head -20
-        echo ""
-        echo "=== Workspace breakdown (top level) ==="
-        du -h --max-depth=1 . 2>/dev/null | sort -rh
-        echo ""
-        echo "=== Workspace breakdown (2 levels deep) ==="
-        du -h --max-depth=2 . 2>/dev/null | sort -rh | head -30
-        echo ""
-        echo "=== externals directory ==="
-        du -sh ./externals/* 2>/dev/null | sort -rh | head -20 || echo "No externals"
-        echo ""
-        echo "=== output directory ==="
-        du -sh ./output/* 2>/dev/null | sort -rh | head -20 || echo "No output"
-        echo ""
-        echo "=== generated directory ==="
-        du -sh ./generated/* 2>/dev/null | sort -rh | head -20 || echo "No generated"
-        echo ""
-        echo "=== /mnt disk usage ==="
-        du -h --max-depth=1 /mnt 2>/dev/null | sort -rh
-        echo ""
-        echo "=== Docker usage ==="
-        docker system df 2>/dev/null || echo "Docker not available"
-        echo ""
-        echo "=== Temp directories ==="
-        du -sh /tmp /var/tmp 2>/dev/null || true
-      fi