[TEST] Configure push workflow for PR-based dry run

DO NOT MERGE - test-only changes to validate push.yaml workflow.
Contains deliberate lint failure to prevent accidental merge.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: anth-volk

.github/workflows/push.yaml

@@ -1,7 +1,7 @@
-name: Push to main
+name: "[TEST] Push workflow dry run"
 
 on:
-  push:
+  pull_request:
     branches: [main]
 
 jobs:
@@ -18,7 +18,6 @@ jobs:
   # ── Download prerequisites ──────────────────────────────────
   download-prerequisites:
     runs-on: ubuntu-latest
-    needs: lint
     if: github.event.head_commit.message != 'Update package version'
     env:
       MODAL_TOKEN_ID: ${{ secrets.MODAL_TOKEN_ID }}

policyengine_us_data/__init__.py

@@ -1,2 +1,3 @@
 from .datasets import *
 from .geography import ZIP_CODE_DATASET
+DO_NOT_MERGE_THIS_PR =        True   # deliberate lint failure