ci(release): run tests with nextest to match rust.yml

Aligns the release workflow's per-target test step with the regular CI
test workflow: uses cargo-nextest with --status-level slow and the ci
profile so release runs get the same timeout headroom and quieter output.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -51,11 +51,13 @@ jobs:
           rustup default stable
           rustup target add ${{ matrix.target }}
 
+      - uses: taiki-e/install-action@773334c0e05d7e699e4d78234494308223f3a2cf # nextest
+
       - name: Build
         run: cargo build --target ${{ matrix.target }} --release
 
       - name: Test
-        run: cargo test --target ${{ matrix.target }} --release
+        run: cargo nextest run --workspace --target ${{ matrix.target }} --release --status-level slow --profile ci
 
       - name: Package
         run: |