Task A5. Adds customer_job_number, planned_start_date, and internal_deadline on sale.order. Customer deadline maps to Odoo's native commitment_date. Creates sale_order_line.py with per-line plating fields: part_catalog_id, coating_config_id, treatment_ids M2M, part_deadline, rush_order. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>