feat(jobs): add x_fc_use_native_jobs flag + SO confirm hook (Task 2.5)

Settings flag controls which SO confirm path runs. Default False
keeps the legacy bridge_mrp / mrp.production flow on entech.
Setting True diverts confirm into fp.job creation.

Both hooks coexist — bridge_mrp's _fp_auto_create_mo and the new
_fp_auto_create_job — but only one creates records per SO confirm
(controlled by the flag).

The new _fp_auto_create_job mirrors bridge_mrp's grouping logic
(x_fc_wo_group_tag), recipe resolution (coating → part), and
traceability fields (origin, sale_order_line_ids).

Settings UI shows the flag in a 'Fusion Plating Jobs' app section
of the standard Configuration menu.

3 new tests cover: flag off no-op, flag on creates job, idempotency.

Manifest 19.0.1.3.0 → 19.0.1.4.0.

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_jobs/models/__init__.py

@@ -7,3 +7,5 @@
 
 from . import fp_job
 from . import fp_job_node_override
+from . import res_config_settings
+from . import sale_order