feat(scripts): add shellspec installation to dfm (#296)

* feat(scripts): add shellspec installation to dfm

Add install-shellspec.sh script that clones shellspec to
~/.cache/shellspec and installs via make to ~/.local/bin.
Wire it into dfm install menu and the Tier 4 install-all pipeline.

* fix(scripts): address PR review feedback for shellspec installer

Add companion install-shellspec.md documentation file to match
codebase convention. Add --depth=1 to git pull for consistent
shallow clone behavior.

* fix(scripts): pin shellspec install to latest release tag

Use x-gh-get-latest-version to fetch the latest release tag from
GitHub and clone/checkout that specific version. Addresses supply
chain concern and normalizes --depth=1 style.

* docs(scripts): update shellspec docs to reflect release-tag pinning

local/bin/dfm

@@ -88,6 +88,7 @@ section_install()
     "nvm-latest:Install latest lts node using nvm"
     "nvm:Install Node Version Manager (nvm)"
     "python-packages:Install Python packages via uv"
+    "shellspec:Install shellspec testing framework"
     "xcode-cli-tools:Install Xcode CLI tools (macOS)"
     "z:Install z"
   )
@@ -121,6 +122,7 @@ section_install()
       $0 install ntfy
 
       # Tier 4: Independent utilities
+      $0 install shellspec
       $0 install z
 
       msgr msg "Reloading configurations again..."
@@ -245,6 +247,12 @@ section_install()
         && msgr yay "Xcode CLI tools installed!"
       ;;
 
+    shellspec)
+      msgr run "Installing shellspec..."
+      bash "$DOTFILES/scripts/install-shellspec.sh" \
+        && msgr yay "shellspec has been installed!"
+      ;;
+
     z)
       msgr run "Installing z..."
       bash "$DOTFILES/scripts/install-z.sh" \

scripts/install-shellspec.md

@@ -0,0 +1,16 @@
+# install-shellspec
+
+Installs [shellspec](https://github.com/shellspec/shellspec), a BDD-style
+testing framework for shell scripts.
+
+## Usage
+
+```bash
+scripts/install-shellspec.sh
+```
+
+The script resolves the latest release tag via `x-gh-get-latest-version`,
+clones shellspec to `~/.cache/shellspec` pinned to that tag, and runs
+`make install PREFIX=$HOME/.local`, placing the binary in `~/.local/bin/`.
+Re-running the script fetches and checks out the newest release tag
+before reinstalling.

scripts/install-shellspec.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+set -euo pipefail
+# @description Install shellspec testing framework
+#
+# shellcheck source=shared.sh
+source "${DOTFILES}/config/shared.sh"
+
+SHELLSPEC_REPO="https://github.com/shellspec/shellspec.git"
+SHELLSPEC_CACHE="$HOME/.cache/shellspec"
+
+install_shellspec()
+{
+  local version
+  version=$(x-gh-get-latest-version shellspec/shellspec)
+  msgr ok "Latest shellspec version: $version"
+
+  if [[ -d "$SHELLSPEC_CACHE" ]]; then
+    msgr ok "shellspec repo already cloned, fetching $version..."
+    git -C "$SHELLSPEC_CACHE" fetch --depth=1 origin "refs/tags/$version"
+    git -C "$SHELLSPEC_CACHE" checkout "$version"
+  else
+    git clone --branch "$version" --depth=1 "$SHELLSPEC_REPO" "$SHELLSPEC_CACHE"
+  fi
+
+  msgr run "Running make install..."
+  make -C "$SHELLSPEC_CACHE" install PREFIX="$HOME/.local"
+  msgr run_done "shellspec $version installed to $HOME/.local/bin/shellspec"
+  return 0
+}
+
+main()
+{
+  install_shellspec
+  return 0
+}
+
+main "$@"