feat(jobs): Phase 7 — migration script + legacy id fields

Adds legacy_mrp_production_id (Integer index) on fp.job and
legacy_mrp_workorder_id on fp.job.step. Used as the idempotency
key during cutover migration.

Three scripts under fusion_plating_jobs/scripts/:
- audit_pre_migration.py   — counts and data-quality concerns BEFORE
- migrate_to_fp_jobs.py    — copies MO->fp.job, WO->fp.job.step, time
                             logs, rebinds cross-refs (batches,
                             holds, certs, readings, portals,
                             inspections, deliveries). Idempotent.
- audit_post_migration.py  — counts and verifies AFTER

Migration is run manually from \`odoo shell\` at cutover (not as
auto post-migration hook, for safety). README explains usage.

Tests verify the legacy id fields exist and the migration script
files are well-formed Python.

Manifest 19.0.1.9.0 -> 19.0.2.0.0.

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/tests/test_fp_job_extensions.py

@@ -574,3 +574,63 @@ class TestPhase6Controllers(TransactionCase):
         step_by_node = {s.recipe_node_id.id: s for s in self.job.step_ids if s.recipe_node_id}
         self.assertIn(op.id, step_by_node)
         self.assertEqual(step_by_node[op.id].name, 'Op1')
+
+
+class TestPhase7Migration(TransactionCase):
+    """Phase 7 — verify the migration script idempotency-key fields are
+    in place and the script files are present + parse as valid Python.
+
+    We cannot run the migration end-to-end in a unit test (it would need
+    a populated MO/WO snapshot). Instead we assert the scaffolding is
+    solid: fields exist, files are well-formed.
+    """
+
+    def test_legacy_id_field_on_fp_job(self):
+        self.assertIn(
+            'legacy_mrp_production_id',
+            self.env['fp.job']._fields,
+        )
+        # Should be Integer (we store the raw db id, not a Many2one — the
+        # source MO may be archived later without breaking the link).
+        self.assertEqual(
+            self.env['fp.job']._fields['legacy_mrp_production_id'].type,
+            'integer',
+        )
+
+    def test_legacy_id_field_on_fp_job_step(self):
+        self.assertIn(
+            'legacy_mrp_workorder_id',
+            self.env['fp.job.step']._fields,
+        )
+        self.assertEqual(
+            self.env['fp.job.step']._fields['legacy_mrp_workorder_id'].type,
+            'integer',
+        )
+
+    def test_migration_script_files_exist_and_parse(self):
+        # Sanity check that the script files we ship are valid Python.
+        # Catches syntax errors that would otherwise only surface on the
+        # cutover engineer's screen at the worst possible moment.
+        import ast
+        from pathlib import Path
+        scripts_dir = (
+            Path(__file__).parent.parent / 'scripts'
+        )
+        for script in (
+            'audit_pre_migration.py',
+            'migrate_to_fp_jobs.py',
+            'audit_post_migration.py',
+        ):
+            path = scripts_dir / script
+            self.assertTrue(path.exists(), '%s missing' % script)
+            with open(path) as f:
+                ast.parse(f.read())  # Will raise SyntaxError if invalid
+
+    def test_scripts_dir_is_a_python_package(self):
+        # __init__.py exists so Odoo's autodiscovery doesn't trip and the
+        # dir is importable for hypothetical future post-migration hooks.
+        from pathlib import Path
+        init = (
+            Path(__file__).parent.parent / 'scripts' / '__init__.py'
+        )
+        self.assertTrue(init.exists())