CI: macos-x86_64 smoke is continue-on-error + 30 min timeout

GitHub's macos-13 (Intel) hosted runners are in chronic short
supply. The smoke-install job for the macos-x86_64 wheel can sit
queued for an hour or more before being picked up, which has been
stalling Wheels (003) runs even though every wheel built cleanly
and publish-release ran 1 minute in.

Two safety nets:
- `continue-on-error: true` on the macos-x86_64 matrix row so a
  failed / stalled smoke does not mark the whole run failed.
- `timeout-minutes: 30` so a row that never gets a runner is
  eventually cancelled by GitHub instead of sitting indefinitely.

The macos-x86_64 BUILD step still runs on the arm64 macos-latest
via maturin cross-compile and stays a hard gate; only the on-host
install verification is best-effort.

Author: AlexMelanFromRingo

.github/workflows/wheels.yml

@@ -116,14 +116,24 @@ jobs:
     name: Wheel smoke (${{ matrix.platform }})
     needs: [linux-x86_64, macos-arm64, macos-x86_64, windows-x86_64]
     runs-on: ${{ matrix.runs-on }}
+    # macos-13 (Intel) runners are in chronic short supply on
+    # hosted GitHub Actions and frequently sit queued > 1 h before
+    # being picked up. The build for macos-x86_64 succeeds via
+    # cross-compile on the arm64 macos-latest, so the smoke-install
+    # on Intel is purely a sanity check. Letting it continue-on-error
+    # at the matrix level means a stalled Intel runner does not stall
+    # the whole run; pair this with the 30-minute job timeout so the
+    # row eventually completes even when the runner never materialises.
+    continue-on-error: ${{ matrix.platform == 'macos-x86_64' }}
+    timeout-minutes: 30
     strategy:
       fail-fast: false
       matrix:
         include:
           - platform: linux-x86_64
             runs-on: ubuntu-latest
           - platform: macos-arm64
-            # macos-latest now defaults to arm64 (M-series).
+            # macos-latest defaults to arm64 (M-series).
             runs-on: macos-latest
           - platform: macos-x86_64
             # macos-13 is the last Intel runner GitHub provides; an