refactor(secubox-core): Modularize luci.secubox RPCD handler
Split 2544-line monolithic handler into thin dispatcher + 14 modules:
- _common.sh: Shared utilities (json_success, check_service_running, etc.)
- core.sh: getStatus, getVersion, reload
- modules.sh: Module management (install, remove, update)
- profiles.sh: Profile management
- snapshots.sh: Snapshot/recovery
- health.sh: Health & diagnostics
- dashboard.sh: Dashboard data & quick actions
- appstore.sh: AppStore & catalog operations
- state.sh: Component state management
- network.sh: WAN access, services, proxy mode
- feeds.sh: Feed management
- skills.sh: Skill management
- feedback.sh: Issue/resolution tracking
- p2p.sh: P2P hub operations
Benefits:
- Each module is focused on a single domain
- Easier to maintain, test, and debug
- New features can be added as new modules
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>