Add shell syntax and ShellCheck CI

Author: 7jin16

.github/workflows/shell.yml

@@ -0,0 +1,18 @@
+name: Shell checks
+
+on:
+  push:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  shell:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check Bash syntax
+        run: bash -n bootstrap.sh install.sh doctor.sh uninstall.sh
+      - name: Run ShellCheck
+        run: shellcheck bootstrap.sh install.sh doctor.sh uninstall.sh