ci: run Windows archive tests in two jobs

Cross-compile the Windows test archive on Linux before starting Windows runners, then run the default suite across two nextest partitions.

Run the smaller Node-backed ignored suite once to avoid duplicate setup while preserving coverage.

Author: claude

.github/workflows/ci.yml

@@ -133,11 +133,12 @@ jobs:
 
   # Windows tests are cross-compiled on a fast Linux runner with cargo-xwin
   # (clang-cl + lld-link against the xwin-downloaded MSVC CRT/Windows SDK)
-  # and packed into a portable nextest archive. The test-windows shards then
-  # only download the archive and run it — no Rust toolchain or compilation
-  # on the slow Windows runners. Windows e2e fixtures dominate wall-clock
-  # (60s per PTY step vs 20s on Unix), so the run is split across shards via
-  # nextest's count partitioning, which spreads tests round-robin.
+  # and packed into a portable nextest archive. The Windows runners then only
+  # download the archive and run it: no Rust toolchain or compilation on the
+  # slow runners. Two nextest partitions avoid most repeated setup while keeping
+  # enough parallelism for the Windows-heavy default test workload. The much
+  # smaller Node-backed ignored suite runs once in the second partition, avoiding
+  # a duplicate Windows Node setup.
   build-windows-tests:
     needs: detect-changes
     if: needs.detect-changes.outputs.code-changed == 'true'
@@ -214,10 +215,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        partition: [1, 2, 3, 4, 5, 6]
+        partition: [1, 2]
     runs-on: windows-latest
     env:
-      PARTITION: count:${{ matrix.partition }}/6
+      PARTITION: count:${{ matrix.partition }}/2
     steps:
       - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
 
@@ -243,11 +244,11 @@ jobs:
         run: cargo-nextest nextest run --archive-file windows-tests.tar.zst --workspace-remap . --partition "$PARTITION"
 
       - uses: oxc-project/setup-node@ab97f03642370d79a7e96dd286bd02a1be40e0ba # v1.3.0
+        if: matrix.partition == 2
 
-      # --no-tests=pass: a shard's partition of the (much smaller) ignored
-      # test set may legitimately come up empty.
       - name: Run ignored tests
-        run: cargo-nextest nextest run --archive-file windows-tests.tar.zst --workspace-remap . --partition "$PARTITION" --run-ignored ignored-only --no-tests pass
+        if: matrix.partition == 2
+        run: cargo-nextest nextest run --archive-file windows-tests.tar.zst --workspace-remap . --run-ignored ignored-only
 
   test-musl:
     needs: detect-changes