Update GitHub Actions

We update things to be a bit more modern:
- We rename the file to not be about `nodejs` (because it never really
    was, that was an implementation detail).
- We trigger on all `pull_request_target` events.
- We trigger on pushes to the `main` or `joneshf/<something>` branches.
- We rename the job from `build` to `test` (because that's what we're
    actually doing: testing).
- We bump the version of `actions/checkout`.
- We switch to using `cachix/install-nix-action`.

It would be nice to have this stuff cached somewhere, but caching with
GitHub Actions plus Nix plus Node.js takes more than a modicum of
effort, so we're not going to deal with it.

Author: joneshf

.github/workflows/nodejs.yml

@@ -0,0 +1,40 @@
+name: Test
+
+on:
+  - push
+
+jobs:
+  test:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+      - name: Install Nix
+        uses: nixbuild/nix-quick-install-action@63ca48f939ee3b8d835f4126562537df0fee5b91
+      - name: Cache Nix store
+        uses: nix-community/cache-nix-action@135667ec418502fa5a3598af6fb9eb733888ce6a
+        with:
+          primary-key: nix-${{ runner.os }}-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}
+          restore-prefixes-first-match: |
+            nix-${{ runner.os }}-${{ hashFiles('flake.lock') }}-
+            nix-${{ runner.os }}-
+      - name: Cache node_modules
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684
+        with:
+          key: node_modules-${{ runner.os }}-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}-${{ hashFiles('**/package-lock.json') }}
+          path: "**/node_modules"
+          restore-keys: |
+            node_modules-${{ runner.os }}-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}-
+            node_modules-${{ runner.os }}-${{ hashFiles('flake.lock') }}-
+            node_modules-${{ runner.os }}-
+      - name: Cache bower_components
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684
+        with:
+          key: bower_components-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}-${{ hashFiles('**/package-lock.json') }}-${{ hashFiles('bower.json') }}
+          path: bower_components
+          restore-keys: |
+            bower_components-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}-${{ hashFiles('**/package-lock.json') }}-
+            bower_components-${{ hashFiles('flake.lock') }}-${{ hashFiles('**/*.nix') }}-
+            bower_components-${{ hashFiles('flake.lock') }}-
+            bower_components-
+      - name: Test
+        run: nix develop . --command make test