Skip publish workflow if version already exists on PyPI (#11)

Added early version check that queries PyPI API to see if current version
already exists. If so, skips all expensive steps (poetry install, tests,
build) and exits early.

This prevents unnecessary CI runs and potential publish conflicts when
the same version is pushed multiple times to main.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: jkebinger

.github/workflows/publish.yml

@@ -26,16 +26,36 @@ jobs:
         with:
           python-version: "3.10"
 
+      - name: Check if version already published
+        id: version-check
+        run: |
+          VERSION=$(cat sdk_reforge/VERSION | tr -d '\n')
+          echo "Current version: $VERSION"
+
+          # Check if this version exists on PyPI
+          HTTP_STATUS=$(curl -s -o /dev/null -w "%{http_code}" "https://pypi.org/pypi/sdk-reforge/$VERSION/json")
+
+          if [ "$HTTP_STATUS" = "200" ]; then
+            echo "Version $VERSION already exists on PyPI"
+            echo "skip=true" >> $GITHUB_OUTPUT
+          else
+            echo "Version $VERSION not found on PyPI, proceeding with publish"
+            echo "skip=false" >> $GITHUB_OUTPUT
+          fi
+
       - name: Install Poetry
+        if: steps.version-check.outputs.skip == 'false'
         uses: snok/install-poetry@v1
         with:
           virtualenvs-create: true
 
       - name: Install dependencies
+        if: steps.version-check.outputs.skip == 'false'
         run: |
           poetry install --no-interaction
 
       - name: Run tests
+        if: steps.version-check.outputs.skip == 'false'
         run: poetry run pytest
         env:
           REFORGE_INTEGRATION_TEST_SDK_KEY: ${{ secrets.REFORGE_INTEGRATION_TEST_SDK_KEY }}
@@ -44,9 +64,11 @@ jobs:
           IS_A_NUMBER: 1234
 
       - name: Build package
+        if: steps.version-check.outputs.skip == 'false'
         run: poetry build
 
       - name: Publish to PyPI
+        if: steps.version-check.outputs.skip == 'false'
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
           packages-dir: dist/