feat(fusion_plating_jobs): de-rack/bake area_kind name override + rack-load Phase 1

- _compute_area_kind: name-based override so de-rack/de-mask steps land in the
  De-Racking column and bake/oven steps in Baking, regardless of a mis-tagged
  recipe kind (fixed WO cards scattering into the wrong shop-floor columns).
- fp.rack.load jobs extension: racking-step resolution by area_kind (not the
  corrupt kind), equal-split/override ops, fp.job qty_racked/unracked rollups,
  and independent rack movement (per-line moves) + de-racking unrack.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_jobs/models/__init__.py

@@ -35,6 +35,10 @@ from . import report_fp_job_margin
 # (fp.qc.checklist.template lives in fusion_plating_quality; can't depend
 # back on jobs without a cycle.)
 from . import fp_job_consumption
+
+# Multi-rack splitting at Racking (Phase 1) — jobs-side extension of
+# fp.rack.load (core model in fusion_plating) + fp.job rollups.
+from . import fp_job_rack
 # fp.work.role, fp.operator.proficiency, fp_process_node inherit, and the
 # hr.employee shop-roles inherit live in fusion_plating core so every
 # downstream module (cgp, bridge_mrp residue, etc.) sees them without a