Speed up CI setup and coverage upload

pnpm/action-setup installs a bootstrap pnpm and then switches to the
packageManager version, about 10 s per job; npm installs it in 3 s.
setup-node took 4 s probing package managers for a cache it never
used. The pnpm store cache took 4 s to restore and 5 s to save, more
than downloading the packages costs, and the build cache no longer pays
off with TypeScript 7: pnpm install is 13-23 s without either cache
against 17-31 s with them.

The Codecov action searched the workspace and uploaded the raw V8
coverage in coverage/tmp next to lcov.info, 72 MB taking 11 s.

The version compatibility job ran tsc --build again after pnpm install
had already built everything.

Cancel superseded runs of branches and pull requests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/node.js.yml

@@ -7,6 +7,12 @@ on:
   push:
   pull_request:
 
+# Superseded runs of a branch or pull request are cancelled. Runs on master
+# each get their own group so every commit there is tested.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref == 'refs/heads/master' && github.sha || github.ref }}
+  cancel-in-progress: true
+
 env:
   NODE_VERSION: 24.x
 
@@ -54,6 +60,8 @@ jobs:
       uses: codecov/codecov-action@v7
       with:
         files: ./coverage/lcov.info
+        # Otherwise the raw V8 coverage in coverage/tmp is uploaded as well
+        disable_search: true
         token: ${{ secrets.CODECOV_TOKEN }}
     - name: Upload test logs for debugging
       if: ${{ !cancelled() }}
@@ -87,8 +95,6 @@ jobs:
       uses: ./.github/actions/pnpm-install
       with:
         node-version: ${{ env.NODE_VERSION }}
-    - name: Build
-      run: pnpm run build
     - name: Test ${{ matrix.controller }} controller with ${{ matrix.host }} host
       run: >
         node scripts/version-compat-test.js