fix(scripts): resolve shellcheck warnings (#148)

AGENTS.md

@@ -0,0 +1,34 @@
+# Project guidelines
+
+This repository contains configuration files and helper scripts for managing a development environment. Dotbot drives the installation and host specific folders under `hosts/` include extra configs.
+
+## Keeping the repository up to date
+
+1. Update submodules with `git submodule update --remote --merge`.
+2. Pull the latest changes and run `./install`.
+3. Run `yarn install` whenever `package.json` changes.
+
+## Linting and tests
+
+- Format files with:
+
+  ```bash
+  yarn fix:prettier
+  yarn fix:markdown
+  ```
+
+- Shell scripts must pass `shellcheck`. Run:
+
+  ```bash
+  find . -path ./node_modules -prune -o -name '*.sh' -print0 | xargs -0 shellcheck
+  ```
+
+- Execute tests with `yarn test`.
+
+## Debugging lint issues
+
+- `yarn lint:prettier` and `yarn lint:markdown` show formatting errors.
+- Ensure shell scripts have a shebang or `# shellcheck shell=bash` directive.
+- Consult `.shellcheckrc` for project specific checks.
+
+Scripts rely on helpers in `config/shared.sh` so they run under Bash, Zsh and Fish by default.