fix: revert to sed, cleaner workflow

.gitea/workflows/update-readme.yaml

@@ -14,6 +14,24 @@ jobs:
           git clone http://gitea-http:3000/${{ github.repository }}.git .
           git checkout ${{ github.ref_name }}
 
+      - name: Update README
+        run: |
+          LOC=$(grep '"total_code"' public/code-stats.json | sed 's/[^0-9]*//g')
+          FORMATTED_LOC=$(printf "%'d" $LOC)
+          
+          grep -v "Codebase Growth" README.md > README.tmp
+          
+          sed -i "/## ⚡ Efficiency Metrics/a \\
+          \\
+          - **Codebase Growth:** $FORMATTED_LOC lines of custom code across all our repositories" README.tmp
+          
+          if [ -s README.tmp ]; then
+            mv README.tmp README.md
+          else
+            echo "Corruption detected, aborting"
+            exit 1
+          fi
+
       - name: Update README
         run: |
           LOC=$(grep '"total_code"' public/code-stats.json | sed 's/[^0-9]*//g')