feat: Veeam VSPC backup integration - sync, compliance, UI
- Database: 7 Veeam tables + backup_type_udf column on configuration_items
- API Client: VSPC REST API v3 client with pagination, rate limiting, Bearer auth
- Sync Service: full/incremental sync for orgs, servers, repos, jobs, agent jobs, workloads
- Scheduler: veeam-incremental (30min) and veeam-full (daily 2AM) schedules
- Compliance Engine: cross-references Autotask config items vs Veeam workloads
- API Endpoints: backup-status, companies, workloads, jobs, repos, compliance, sync
- UI: Backup Status page with Overview + Contract Compliance tabs
- Navigation: added Backup Status link with HardDrive icon
- Docker: added VEEAM_VSPC_URL and VEEAM_VSPC_API_KEY env vars to compose