feat(configurator): OWL widgets + Express form polish to match mockup

NEW OWL widgets:
- FpExpressPartCell (static/src/js/express_part_cell.js + .xml) — multi-row
  Part cell. Wraps Many2OneField for the part picker (row 1: part# / rev,
  bold). Below it: row 2 part description (italic muted), row 3 serial #s
  joined + '+ bulk' button that triggers the existing bulk-add wizard.
- FpExpressBakePill (static/src/js/express_bake_pill.js + .xml) — click-
  to-edit Bake pill. Renders amber pill when set, italic muted 'no bake'
  when empty. Click swaps to inline textarea + Save / Clear / Cancel.

NEW fields:
- fp.direct.order.line.part_number_display / part_revision_display /
  part_name_display (related Char from fp.part.catalog) — fed to the
  Part cell widget so it can render multi-row without RPC.
- fp.direct.order.wizard.tooling_charge (Monetary) — surfaced in the
  Totals card on the Express form.
- fp.direct.order.wizard.po_status (computed Selection
  received/pending/missing) — drives the PO Block status badge.
- sale.order.x_fc_tooling_charge (Monetary) — receives wizard.tooling_charge
  at confirm.

View updates (fp_express_order_views.xml):
- PO block header now shows the PO status pill (green Received,
  amber Pending, red Missing)
- Order Lines legend bar (Mask / Bake pill / DWG / OPEN explainers)
- Part Number column uses widget='fp_express_part_cell' — single cell
  with 3 internal rows
- Bake column uses widget='fp_express_bake_pill' — interactive pill
- Totals card now has Subtotal / Tooling Charge / Total Lines / Total
  Quantity / Grand Total + currency pill

SCSS adds:
- Multi-row part cell styles (internal borders, bold/italic/muted rows)
- Bake pill (has-bake amber, no-bake italic muted) + inline editor
- Legend bar (section background, gap-spaced explainer chips)
- PO status pill colour scheme
- Bulk button styling

Wizard's action_create_order now carries tooling_charge to the SO at
confirm so it persists on the resulting sale.order.

fusion_plating/fusion_plating_configurator/models/sale_order.py

@@ -140,6 +140,12 @@ class SaleOrder(models.Model):
         help='When False, the Terms & Conditions (sale.order.note) is '
              'suppressed on quote / SO / invoice / packing slip PDFs.',
     )
+    x_fc_tooling_charge = fields.Monetary(
+        string='Tooling Charge',
+        currency_field='currency_id',
+        help='Optional one-time tooling fee from the Express Orders form. '
+             'Surfaced on the invoice as a separate line.',
+    )
     x_fc_planned_start_date = fields.Date(
         string='Planned Start Date', tracking=True,
     )