Add GitHub Actions workflow for PR line counting with PR comments (#162)

* Add GitHub Action workflow for PR line counting

Co-authored-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

* Improve workflow: use env variable and more robust line counting

Co-authored-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

* Add explicit permissions to workflow for security

Co-authored-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

* Add PR commenting and improve line counting for files without trailing newlines

Co-authored-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: functionstackx <47992694+functionstackx@users.noreply.github.com>

Author: Copilot

.github/workflows/pr-line-counter.yml

@@ -0,0 +1,71 @@
+name: PR Line Counter
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  count-lines:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    env:
+      TARGET_FILE: utils/matrix-logic/generate_sweep_configs.py
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Count lines in generate_sweep_configs.py
+        id: line-count
+        run: |
+          if [ -f "$TARGET_FILE" ]; then
+            LINE_COUNT=$(wc -l < "$TARGET_FILE")
+            # If the last character is not a newline, increment the count
+            if [ -n "$(tail -c 1 "$TARGET_FILE" | tr -d '\n')" ]; then
+              LINE_COUNT=$((LINE_COUNT + 1))
+            fi
+            echo "line_count=$LINE_COUNT" >> $GITHUB_OUTPUT
+            echo "file_exists=true" >> $GITHUB_OUTPUT
+          else
+            echo "file_exists=false" >> $GITHUB_OUTPUT
+            echo "line_count=0" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Generate summary
+        run: |
+          echo "## 📊 Line Count Report" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+
+          FILE_EXISTS="${{ steps.line-count.outputs.file_exists }}"
+          if [ "$FILE_EXISTS" == "true" ]; then
+            LINE_COUNT="${{ steps.line-count.outputs.line_count }}"
+            echo "**File:** \`$TARGET_FILE\`" >> $GITHUB_STEP_SUMMARY
+            echo "" >> $GITHUB_STEP_SUMMARY
+            echo "**Total Lines:** $LINE_COUNT" >> $GITHUB_STEP_SUMMARY
+          else
+            echo "⚠️ **File not found:** \`$TARGET_FILE\`" >> $GITHUB_STEP_SUMMARY
+          fi
+
+      - name: Comment on PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fileExists = '${{ steps.line-count.outputs.file_exists }}';
+            const lineCount = '${{ steps.line-count.outputs.line_count }}';
+            const targetFile = process.env.TARGET_FILE;
+
+            let commentBody;
+            if (fileExists === 'true') {
+              commentBody = `## 📊 Line Count Report\n\n**File:** \`${targetFile}\`\n\n**Total Lines:** ${lineCount}`;
+            } else {
+              commentBody = `## 📊 Line Count Report\n\n⚠️ **File not found:** \`${targetFile}\``;
+            }
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: commentBody
+            });