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

Header model replacing mrp.production. mail.thread for chatter,
priority/state/deadline tracking, sequence WH/JOB/00001+. Tests
cover create, confirm, cancel, and forbidden double-confirm.

State machine:
  draft -> confirmed -> in_progress -> done
              v                          ^
          cancelled              (rework reverts here)
  on_hold can be entered from confirmed or in_progress.

Step relations come in Task 1.5; SO/recipe/portal/cost extension
fields come in Task 1.4.

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/tests/__init__.py

@@ -1,2 +1,3 @@
 # -*- coding: utf-8 -*-
 from . import test_fp_work_centre
+from . import test_fp_job_state_machine

fusion_plating/fusion_plating/tests/test_fp_job_state_machine.py

@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+from odoo.tests.common import TransactionCase
+from odoo.exceptions import UserError
+
+
+class TestFpJobStateMachine(TransactionCase):
+    def setUp(self):
+        super().setUp()
+        self.partner = self.env['res.partner'].create({'name': 'Test Customer'})
+        self.product = self.env['product.product'].create({'name': 'Widget'})
+
+    def _make_job(self, **kw):
+        vals = {
+            'partner_id': self.partner.id,
+            'product_id': self.product.id,
+            'qty': 10.0,
+        }
+        vals.update(kw)
+        return self.env['fp.job'].create(vals)
+
+    def test_create_lands_in_draft(self):
+        job = self._make_job()
+        self.assertEqual(job.state, 'draft')
+        self.assertTrue(job.name and job.name.startswith('WH/JOB/'))
+
+    def test_action_confirm_moves_to_confirmed(self):
+        job = self._make_job()
+        job.action_confirm()
+        self.assertEqual(job.state, 'confirmed')
+
+    def test_cannot_confirm_twice(self):
+        job = self._make_job()
+        job.action_confirm()
+        with self.assertRaises(UserError):
+            job.action_confirm()
+
+    def test_cancel_from_draft(self):
+        job = self._make_job()
+        job.action_cancel()
+        self.assertEqual(job.state, 'cancelled')
+
+    def test_cannot_confirm_after_cancel(self):
+        job = self._make_job()
+        job.action_cancel()
+        with self.assertRaises(UserError):
+            job.action_confirm()