feat(jobs): add fp.job.step model with state machine

Per-operation model replacing mrp.workorder for plating. Each step
instantiates from a recipe operation node (recipe_node_id link).
Container/step nodes from the recipe template are rendered at view
time via that link — they don't get rows here. See spec §5.2
Option A.

7-state machine: pending → ready → in_progress → done, plus
paused, skipped, cancelled. button_start/button_finish enforce
the transitions.

Job header gets step_ids + step_count, step_done_count,
step_progress_pct, current_step_id (computed from steps).

Equipment, audit fields, plating-spec fields, time logs, and
release-ready validation come in Tasks 1.6 and 1.7.

Manifest 19.0.8.3.1 → 19.0.8.4.0.

Part of: native job model migration (spec 2026-04-25)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating/__manifest__.py

@@ -5,7 +5,7 @@
 
 {
     'name': 'Fusion Plating',
-    'version': '19.0.8.3.1',
+    'version': '19.0.8.4.0',
     'category': 'Manufacturing/Plating',
     'summary': 'Core plating / metal finishing ERP: facilities, processes, tanks, baths, jobs, operators.',
     'description': """