ci(installer): pin actions to SHAs, add ShellCheck, drop redundant steps

.github/workflows/install-script-ci.yml

@@ -14,18 +14,15 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - name: Bash syntax check
-        run: bash -n install.sh
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
+
+      - name: ShellCheck
+        uses: ludeeus/action-shellcheck@00cae500b08a931fb5698e11e79bfbd38e612a38 # 2.0.0
 
   smoke-test:
     needs: lint
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # 4.2.2
       - name: Run installer end-to-end
         run: ./install.sh
-      - name: Wait for health endpoint
-        run: |
-          timeout 120 bash -c \
-            'until curl -fsS http://localhost:8321/v1/health; do sleep 1; done'