Bulk-creates jobs from an uploaded XLSX file. Each sheet name must exactly match an existing Job Category name. Row cap is 1000 per sheet. Validates job_title (required), customer_email (regex), job_type (NEW|REVISIT, defaults NEW), job_priority (HIGH|LOW|MEDIUM|URGENT, defaults LOW), scheduling dates, lat/lon pairing, and — if the first pass has zero errors — a second DB-backed pass validating customer/organization/property/job_status/assigned_user existence and relationships. Jobs are created sequentially; on any validation failure, nothing is created and all accumulated errors are returned together.