feat: add PR size check to CI

Refs #561

.gitea/workflows/ci.yml

@@ -11,6 +11,34 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 2
+
+      - name: "HARD RULE: Net lines added must be <= 10"
+        run: |
+          echo "=== PR Size Budget: 10 lines net max ==="
+          git diff --shortstat HEAD^ HEAD > diffstat.txt
+          cat diffstat.txt
+          INSERTIONS=$(grep "insertion" diffstat.txt | awk '{print $4}' | sed 's/([+-])//g' || echo 0)
+          DELETIONS=$(grep "deletion" diffstat.txt | awk '{print $6}' | sed 's/([+-])//g' || echo 0)
+          if [ -z "$INSERTIONS" ]; then INSERTIONS=0; fi
+          if [ -z "$DELETIONS" ]; then DELETIONS=0; fi
+          NET_LINES=$(($INSERTIONS - $DELETIONS))
+          echo "--> Insertions: $INSERTIONS"
+          echo "--> Deletions: $DELETIONS"
+          echo "--> Net change: $NET_LINES lines"
+          if [ "$NET_LINES" -gt 10 ]; then
+            echo ""
+            echo "══════════════════════════════════════════════════════════════"
+            echo "  BLOCKED: Net lines added must be less than or equal to 10."
+            echo "  Make this PR smaller, or find something to delete."
+            echo "  (See CONTRIBUTING.md for details)"
+            echo "══════════════════════════════════════════════════════════════"
+            exit 1
+          else
+            echo "OK: Net change is within budget."
+          fi
+
 
       - name: Validate HTML
         run: |