CI: Upload PNG snapshot artifacts on test failure

This temporarily adds artifact upload for PNG snapshots when tests fail,
specifically for debugging the failing og_image snapshot tests.

Author: Turbo87

.github/workflows/ci.yml

@@ -189,6 +189,16 @@ jobs:
       - run: cargo build --tests --workspace
       - run: cargo test --workspace
 
+      - name: Upload PNG snapshot artifacts on test failure
+        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4
+        if: failure()
+        with:
+          name: insta-snapshots-png
+          path: |
+            crates/crates_io_og_image/src/snapshots/*.png
+            crates/crates_io_og_image/src/snapshots/*.snap.new.png
+          retention-days: 14
+
   frontend-lint:
     name: Frontend / Lint
     runs-on: ubuntu-24.04