align Herdr keyboard shortcuts

[BrettKinny]

Summary

• generate a Herdr default that follows the shared keyboard language: Super for OS/window-manager actions, Ctrl for immediate app actions, and Shift to modify or move
• retain F12-prefixed compatibility fallbacks and preserve existing user-managed Herdr configuration
• publish new configuration atomically with symlink-safe handling
• document the shared language and add provisioning regression coverage

Why

Squarebox is intended to provide a consistent terminal environment across devices. Aligning Herdr with the same shortcut grammar used by the surrounding Omarchy and Windows dotfiles makes its controls portable and predictable.

Validation

• bash tests/test-provision-state.sh — 30/30 passed
• bash tests/test-provision-install-failures.sh — 61/61 passed
• git diff --check
• bash -n setup.sh tests/test-provision-state.sh