ci: bring host-cpp-tests in line with the rest of the workflow (#408)

* ci: bring host-cpp-tests in line with the rest of the workflow

host-cpp-tests was added on next (#398), so the Node.js 20 deprecation
sweep on main (#405, #407) never reached it: it is the one job in the
workflow still on actions/checkout@v4, pnpm/action-setup@v4 and
actions/setup-node@v6, and so the only remaining source of the runner's
"targets Node.js 20" warning.

Merges main to pick up #407 and gives the job the same arrangement as
its siblings: Node.js set up before pnpm, pnpm/action-setup v6 owning
the store cache, and ccache-action pinned to an exact patch.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W14eEfXdK5DYzv43MazryE

* ci: re-run checks for the newly applied labels

check.yml only runs on opened/synchronize/reopened, so the host-gated
job this change is about does not start from labelling alone.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W14eEfXdK5DYzv43MazryE

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: kraenhansen

.github/workflows/check.yml

@@ -171,18 +171,19 @@ jobs:
     runs-on: ${{ matrix.runner }}
     name: Host C++ tests (${{ matrix.runner }})
     steps:
-      - uses: actions/checkout@v4
-      - uses: pnpm/action-setup@v4
-      - uses: actions/setup-node@v6
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
         with:
           node-version: lts/krypton
-          cache: pnpm
+      - uses: pnpm/action-setup@v6
+        with:
+          cache: true
       - name: Setup cpp tools
         uses: aminya/setup-cpp@v1
         with:
           clang-format: true
       - name: ccache
-        uses: hendrikmuhs/ccache-action@v1.2
+        uses: hendrikmuhs/ccache-action@v1.2.23
         with:
           key: ${{ github.job }}-${{ runner.os }}
       - run: pnpm install