Add tile-quad and tile-dual scripts

[lukasjuhas]

Summary

• New src/bin/tile-quad opens 4 Terminal.app windows in a 2x2 grid
• New src/bin/tile-dual opens 2 Terminal.app windows side-by-side
• Both cd into a starting directory (default ~/projects, overridable via first arg)
• Uses AppleScript via osascript to read screen bounds from Finder and set window bounds — no extra dependencies
• src/bin/ is already on $PATH so the commands work directly once merged

Test plan

• Run tile-quad from any terminal — first run will prompt for Automation permissions for both Finder and Terminal; approve both
• Confirm 4 windows fill the screen as a clean 2x2 grid, each at ~/projects
• Run tile-dual — confirm 2 windows fill the screen side-by-side
• Run tile-quad ~/some/other/dir — confirm windows open in that directory
• (Optional) Add ~/projects/dotfiles/src/bin/ to Raycast Script Commands and bind hotkeys

Notes

• Tiling area excludes the menu bar and Dock automatically (uses Finder's desktop bounds)
• Main display only — multi-monitor would need a rewrite using system_profiler or a Swift shim
• For the second-desktop use case (2 columns), swipe to that Space and run tile-dual — macOS Spaces aren't reliably scriptable without yabai