Replace all 32 unchecked type assertions (result.(Type)) with safe
ok-pattern checks that return descriptive errors on type mismatch.
Complete stub handlers in tools_window.go (restore, title, visibility,
fullscreen) and tools_layout.go (save, restore, list, delete, get,
tile, snap) using proper IPC message types instead of workarounds.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
