fix(ci): trigger PyPI publish after Release workflow completes

.github/workflows/pypi.yml

@@ -1,8 +1,9 @@
 name: Publish to PyPI
 
 on:
-  release:
-    types: [published]
+  workflow_run:
+    workflows: ["Release"]
+    types: [completed]
   workflow_dispatch:
     inputs:
       tag:
@@ -14,7 +15,11 @@ jobs:
   publish:
     name: Publish to PyPI
     runs-on: ubuntu-latest
-    if: github.repository == '35C4n0r/langgraph-ephemeral-checkpointer'
+    if: |
+      github.repository == '35C4n0r/langgraph-ephemeral-checkpointer' && (
+        github.event_name == 'workflow_dispatch' ||
+        github.event.workflow_run.conclusion == 'success'
+      )
     environment:
       name: pypi
       url: https://pypi.org/project/langgraph-ephemeral-checkpointer/
@@ -24,8 +29,17 @@ jobs:
       contents: read
 
     steps:
+      - name: Resolve tag
+        id: tag
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            echo "value=${{ inputs.tag }}" >> "$GITHUB_OUTPUT"
+          else
+            echo "value=${{ github.event.workflow_run.head_branch }}" >> "$GITHUB_OUTPUT"
+          fi
+
       - name: Download release assets
-        run: gh release download ${{ github.event.release.tag_name || inputs.tag }} --dir dist/ --repo ${{ github.repository }}
+        run: gh release download ${{ steps.tag.outputs.value }} --dir dist/ --repo ${{ github.repository }}
         env:
           GH_TOKEN: ${{ github.token }}