ci: test both push and pull_request events

I think we have a bug with pull_request events so...

.forgejo/workflows/test-pr.yml

@@ -0,0 +1,33 @@
+on:
+  pull_request:
+jobs:
+  report-size-pr:
+    runs-on: nixos
+    steps:
+      - uses: "https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683" # v4
+      - run: nix --version
+      - name: Create Size Report
+        uses: ./
+        with:
+          # Create a comment on the associated PR
+          comment-on-pr: 'true'
+          # Generate artifacts on main (to speed up comparisons)
+          # generate-artifact: ${{ github.ref_name == 'main' }}
+          # Always generate artifacts for testing purposes
+          generate-artifact: 'true'
+          # Generate comparisons to main
+          do-comparison: 'true'
+          # Get the previous artifacts from report-size-push (since those run on main)
+          job-name: report-size
+          artifact-name: report.json
+  report-download-check-pr:
+    runs-on: nixos
+    needs: report-size-pr
+    steps:
+      - name: Download previous report
+        uses: https://git.salame.cl/actions/download-artifact@d8d0a99033603453ad2255e58720b460a0555e1e # v4
+        with:
+          name: report.json
+      - name: Verify report exists
+        run: |
+          cat report.json