feat(configurator): Phase D batch 2 — active WOs stat button on SO form

D3 first half: x_fc_workorder_count computes live count of active MRP
work orders linked to this SO (via mo.origin = so.name). Adds a
'Active WOs' smart button next to the existing PO / RFQ buttons on
the sale.order form. Clicking opens a filtered mrp.workorder list
grouped by MO.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_configurator/models/sale_order.py

@@ -114,6 +114,33 @@ class SaleOrder(models.Model):
         compute='_compute_margin',
     )
 
+    x_fc_workorder_count = fields.Integer(
+        string='Active WOs',
+        compute='_compute_workorder_count',
+    )
+
+    def _compute_workorder_count(self):
+        WO = self.env['mrp.workorder'].sudo()
+        for rec in self:
+            if not rec.name:
+                rec.x_fc_workorder_count = 0
+                continue
+            rec.x_fc_workorder_count = WO.search_count([
+                ('production_id.origin', '=', rec.name),
+                ('state', 'not in', ('done', 'cancel')),
+            ])
+
+    def action_view_workorders(self):
+        self.ensure_one()
+        return {
+            'type': 'ir.actions.act_window',
+            'name': 'Work Orders',
+            'res_model': 'mrp.workorder',
+            'view_mode': 'list,form',
+            'domain': [('production_id.origin', '=', self.name)],
+            'context': {'search_default_group_production_id': 1},
+        }
+
     @api.depends('commitment_date')
     def _compute_deadline_countdown(self):
         from datetime import datetime