feat(jobs): add fp.job.step.timelog for granular timer tracking

Each button_start opens a fresh timelog row; button_finish closes
the open row and recomputes step.duration_actual as the sum of all
interval durations. Replicates Odoo MRP's mrp.workorder.time_ids
granularity natively (no mrp dep).

Schema: step_id (M2O cascade), user_id, date_started,
date_finished, duration_minutes (computed, stored).

ACLs: operator get create permission on timelogs because
button_start creates them.

Tests: test_start_creates_timelog (asserts the log row exists,
date_finished is False, user_id is the current user) and
test_finish_closes_timelog (asserts log gets date_finished, has a
non-negative duration, and step.duration_actual matches).

Manifest 19.0.8.5.1 -> 19.0.8.6.0.

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/tests/test_fp_job_step_state_machine.py

@@ -120,3 +120,40 @@ class TestFpJobStepStateMachine(TransactionCase):
         # Force recompute via invalidate (Odoo recomputes on next read).
         step.invalidate_recordset(['cost_total'])
         self.assertEqual(step.cost_total, 60.0)
+
+
+class TestFpJobStepTimeLog(TransactionCase):
+    def setUp(self):
+        super().setUp()
+        self.partner = self.env['res.partner'].create({'name': 'Cust'})
+        self.product = self.env['product.product'].create({'name': 'Widget'})
+        self.wc = self.env['fp.work.centre'].create({
+            'name': 'WC', 'code': 'WC', 'kind': 'wet_line',
+        })
+        self.job = self.env['fp.job'].create({
+            'partner_id': self.partner.id,
+            'product_id': self.product.id,
+            'qty': 1.0,
+        })
+        self.step = self.env['fp.job.step'].create({
+            'job_id': self.job.id,
+            'name': 'S',
+            'sequence': 10,
+            'work_centre_id': self.wc.id,
+            'state': 'ready',
+        })
+
+    def test_start_creates_timelog(self):
+        self.step.button_start()
+        self.assertEqual(len(self.step.time_log_ids), 1)
+        self.assertFalse(self.step.time_log_ids[0].date_finished)
+        self.assertEqual(self.step.time_log_ids[0].user_id, self.env.user)
+
+    def test_finish_closes_timelog(self):
+        self.step.button_start()
+        self.step.button_finish()
+        log = self.step.time_log_ids[0]
+        self.assertTrue(log.date_finished)
+        self.assertGreaterEqual(log.duration_minutes, 0.0)
+        # duration_actual on the step should match the sum of timelog durations
+        self.assertEqual(self.step.duration_actual, log.duration_minutes)