chore: add ast-grep rule to convert Optional[T] to T | None (#25560)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

.github/workflows/autofix.yml

@@ -28,7 +28,27 @@ jobs:
         run: |
           uvx --from ast-grep-cli sg --pattern 'db.session.query($WHATEVER).filter($HERE)' --rewrite 'db.session.query($WHATEVER).where($HERE)' -l py --update-all
           uvx --from ast-grep-cli sg --pattern 'session.query($WHATEVER).filter($HERE)' --rewrite 'session.query($WHATEVER).where($HERE)' -l py --update-all
-
+          # Convert Optional[T] to T | None (ignoring quoted types)
+          cat > /tmp/optional-rule.yml << 'EOF'
+          id: convert-optional-to-union
+          language: python
+          rule:
+            kind: generic_type
+            all:
+              - has:
+                  kind: identifier
+                  pattern: Optional
+              - has:
+                  kind: type_parameter
+                  has:
+                    kind: type
+                    pattern: $T
+          fix: $T | None
+          EOF
+          uvx --from ast-grep-cli sg scan --inline-rules "$(cat /tmp/optional-rule.yml)" --update-all
+          # Fix forward references that were incorrectly converted (Python doesn't support "Type" | None syntax)
+          find . -name "*.py" -type f -exec sed -i.bak -E 's/"([^"]+)" \| None/Optional["\1"]/g; s/'"'"'([^'"'"']+)'"'"' \| None/Optional['"'"'\1'"'"']/g' {} \;
+          find . -name "*.py.bak" -type f -delete
 
       - name: mdformat
         run: |