refactor(jobs): address code review feedback on fp.job (Task 1.4)

- Move NOTE comment from between @api.depends and the function
  into a proper docstring on _compute_costs.
- Make currency_id required=True (default still in place — only
  a programmatic write would null it, but Monetary fields need a
  non-null anchor).
- Add test_current_location_for_confirmed to cover the title-case
  fallback branch in _compute_current_location.

Manifest 19.0.8.3.0 → 19.0.8.3.1.

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': '19.0.8.3.0',
+    'version': '19.0.8.3.1',
     'category': 'Manufacturing/Plating',
     'summary': 'Core plating / metal finishing ERP: facilities, processes, tanks, baths, jobs, operators.',
     'description': """