v1.0.0

Changelog

• d9aa210 Testing > 33 tests pass across 4 packages (config, cron, crontab, model).
• 753edf8 build: track go module checksums
• cb7300c feat: implement TODO items 2.5, 5.3, 7.4, 7.5, 10.1, 10.2, 12.1, 12.2
• 024deff feat: initial crontui project
• 590a2c2 fix: add missing max() helper function
• ba5078c fix: centralize command execution to prevent injection
• efff9a1 fix: code audit - remove dead code, fix go.mod, add tests and presets
• 2b558cc fix: harden cli argument parsing and preview validation
• 5436962 fix: make crontab writes and restores lossless
• 3c94af3 fix: preserve raw crontab content during parsing
• 53295d6 fix: remove misleading working directory and mailto editing
• df57828 fix: use safe write paths and surface real crontab errors