feat(fusion_plating): Sub 3 — process_node gets part_catalog_id, cloned_from_id, treatment_uom; opt_in_out label rename (Task 1)

fusion_plating/fusion_plating/models/fp_process_node.py

@@ -172,9 +172,9 @@ class FpProcessNode(models.Model):
     )
     opt_in_out = fields.Selection(
         [
-            ('disabled', 'Disabled'),
-            ('opt_in', 'Opt-In'),
-            ('opt_out', 'Opt-Out'),
+            ('disabled', 'Always Included'),
+            ('opt_out', 'Included by Default'),
+            ('opt_in', 'Excluded by Default'),
         ],
         string='Opt In/Out',
         default='disabled',
@@ -199,6 +199,39 @@ class FpProcessNode(models.Model):
         tracking=True,
     )
 
+    # ---- Part ownership & provenance (Sub 3) --------------------------------
+
+    # Sub 3 — part ownership. NULL on shared templates (admin-managed);
+    # populated on every node in a part's cloned tree.
+    part_catalog_id = fields.Many2one(
+        'fp.part.catalog',
+        string='Part',
+        ondelete='cascade',
+        index=True,
+        help='Populated on nodes that belong to a specific part\'s '
+             'composed process tree. NULL on shared templates.',
+    )
+    # Sub 3 — source-template reference on cloned nodes. Enables
+    # future "template drifted" indicators. Optional, not load-bearing.
+    cloned_from_id = fields.Many2one(
+        'fusion.plating.process.node',
+        string='Cloned From',
+        ondelete='set null',
+        help='On a part-cloned node, points back at the source template '
+             'node it was copied from.',
+    )
+    # Sub 3 — per-node treatment UoM for pricing / cost tracking.
+    treatment_uom = fields.Selection(
+        [
+            ('lbs',   'Lbs (weight-based)'),
+            ('sq_in', 'Sq in (area-based)'),
+        ],
+        string='Treatment UoM',
+        help='How this process step is measured for costing / pricing. '
+             'Picks which physical property of the part to multiply by '
+             'the per-unit rate: weight (Lbs) or surface area (Sq in).',
+    )
+
     # ---- Recipe-only fields (apply when node_type='recipe') -----------------
     # These migrate Steelhead's recipe-level metadata: lead time, the
     # product/service tied to this recipe, the contract review approver