Flatten directory structure and update documentation

- Moved all files from mac_os/ subdirectory to repository root
- Updated README.adoc to reflect simplified architecture
- Updated QUICK_INSTALL.md with all current apps
- Added claude-cli to install.sh and bin/install_homebrew_formulas
- Repository now shows clean file structure without nested mac_os folder
- Documentation now accurately describes opinionated installer approach

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/installers.sh

@@ -0,0 +1,27 @@
+#! /usr/bin/env bash
+
+# Defines software installer functions.
+
+# Label: Install Homebrew
+# Description: Install and setup Homebrew.
+install_homebrew() {
+  if ! command -v brew > /dev/null; then
+    /bin/bash -c "$(curl --location --fail --silent --show-error https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+
+    # Determine Homebrew path based on architecture
+    local brew_path="/opt/homebrew/bin/brew"
+    if [[ "$(/usr/bin/arch)" != "arm64" ]]; then
+      brew_path="/usr/local/bin/brew"
+    fi
+
+    # Add to shell profile for future sessions
+    if [[ ! -f "$HOME/.zprofile" ]] || ! grep -q "brew shellenv" "$HOME/.zprofile"; then
+      echo >> "$HOME/.zprofile"
+      echo "eval \"\$($brew_path shellenv)\"" >> "$HOME/.zprofile"
+    fi
+
+    # Set up PATH for current session
+    eval "$($brew_path shellenv)"
+  fi
+}
+export -f install_homebrew