Task A2 of the direct-order-wizard rewrite. Adds SO-header fields for customer job #, three deadlines (planned start / internal / customer), bill-to / ship-to address pickers, the line_ids O2M linking to fp.direct.order.line, computed order totals, and a missing-info warning banner. Partner onchange now also seeds default addresses. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>