Initial setup: mac_os installer with custom config

Contains both components needed for Mac setup:
- mac_os/: Installer scripts (from bkuhlmann/mac_os)
- mac_os-config/: Custom app configuration

Configured apps:
- Homebrew formulas: atuin, bash, ffmpeg, mas, mole, node, rename, ykman
- Homebrew casks: chromium, deepl, element, nextcloud, nova, proton suite, signal, transmit
- App Store: Affinity suite, Bitwarden, Final Cut Pro, Invoice Ninja, iWork, PastePal, xSearch

Usage: cd mac_os && ./bin/run

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

mac_os-config/bin/install_applications

@@ -0,0 +1,7 @@
+#! /usr/bin/env bash
+
+# Installs non-App Store, non-Homebrew applications.
+# Add custom app installations here using functions from lib/installers.sh:
+#   install_dmg_app, install_zip_app, install_bare_pkg, etc.
+
+# Currently empty - all apps are installed via Homebrew or App Store.