Omarchy shell migration prep and menu selector compatibility

[timmo001]

Summary

Prepares shell scripts for the Omarchy 4 Quickshell migration by abstracting menu selection behind a compatibility helper, refactoring duplicated systemd doctor checks, and adding a dbus-based resume monitor.

Supersedes PR #11 (closed).

Commits

1. Prepare Omarchy shell script migration — on-resume script with shell indicator refresh, migration plan docs
2. Add Omarchy shell resume monitor — dbus sleep/wake monitor (on-resume-monitor), systemd user service
3. Check resume monitor in dot doctor — doctor check for monitor script + unit presence and enablement
4. Document Omarchy Quickshell migration plan — dot-migration/omarchy-quickshell/README.md checklist
5. Refactor: deduplicate systemd doctor checks and inline resume helper — shared checkRequiredUserUnitSetup generic, constants, inlined run_resume_recovery()
6. Feat: add Omarchy menu selector compatibility — menu_select() helper in twitch-menu, workspace-menu, workspace-relayout

Menu Selector Compatibility

Added menu_select() helper to three scripts that:

1. Prefers omarchy-menu-select with positional args (works on Omarchy 3 Walker-backed and Omarchy 4 shell-IPC-backed versions)
2. Falls back to omarchy-launch-walker --dmenu for environments without omarchy-menu-select
3. Passes options as args (not stdin) for cross-version compatibility
4. Omits trailing ellipsis from prompts (omarchy-menu-select appends its own)

workspace-relayout also adds a menu_selector_available() guard and generic error notification.

Doctor Check Refactor

• Extracted RequiredUserUnitSetup interface and checkRequiredUserUnitSetup generic helper
• Consolidated checkDoctorStartup and checkResumeMonitor into declarative config objects
• Added shared constants: USER_SYSTEMD_DIR, userSystemdUnitPath(), DOCTOR_STARTUP_NOTIFY_SCRIPT, RESUME_MONITOR_SCRIPT
• No behaviour change; all messages, severities, and guidance preserved

Validation

• bash -n passes on all modified shell scripts
• bunx tsc --noEmit passes
• bun run build passes
• bun run format applied (no unformatted code)
• Fallow audit: pass (0 introduced dead code, 0 new complexity, 0 duplication)

Context

This is prep work for the Omarchy 4 Quickshell migration. On Omarchy 3, omarchy-menu-select is Walker-backed and requires ≥2 args. Omarchy 4 replaces it with a shell-IPC-backed version that also accepts stdin. By abstracting behind menu_select(), these scripts will work on both versions without modification when the shell migration happens.