feat: enable /ultraplan and harden GrowthBook fallback chain

[amDosion]

Summary

• Enable /ultraplan: Add ULTRAPLAN build flag, move command out of INTERNAL_ONLY_COMMANDS, remove ant-only gate, decompile UltraplanChoiceDialog and UltraplanLaunchDialog from official CLI 2.1.92
• Harden GrowthBook fallback: Ensure LOCAL_GATE_DEFAULTS are consulted even when global config is not yet initialized (early startup)
• Improve Away Summary: Add idle-based detection for terminals without DECSET 1004 focus events (CMD, PowerShell)
• Add cron management skills: Register /cron-list and /cron-delete bundled skills
• Fix fullscreen gate: Restrict isFullscreenEnvEnabled() to ant-only

Changed files (13)

File	Change
build.ts	+ULTRAPLAN build flag
scripts/dev.ts	+ULTRAPLAN dev flag
src/commands.ts	Move ultraplan to public commands
src/commands/ultraplan.tsx	isEnabled → () => true
src/components/ultraplan/UltraplanChoiceDialog.tsx	New — decompiled from 2.1.92
src/components/ultraplan/UltraplanLaunchDialog.tsx	New — decompiled from 2.1.92
src/hooks/useAwaySummary.ts	Idle-based away detection for Windows
src/screens/REPL.tsx	Add 3 missing imports
src/services/analytics/growthbook.ts	Fallback chain hardening
src/skills/bundled/cronManage.ts	New — cron list/delete skills
src/skills/bundled/index.ts	Register cron skills
src/utils/fullscreen.ts	Gate to ant-only
DEV-LOG.md	Development log update

Test plan

• bun run build passes (480 files)
• bun run lint passes (only pre-existing biome-ignore warnings)
• /ultraplan command visible and launchable
• Remote CCR session created and plan returned via UltraplanChoiceDialog
• /cron-list and /cron-delete with active KAIROS cron jobs
• Away summary triggers on Windows CMD/PowerShell after 5min idle

[amDosion]