feat(jobs): persist deadlines + planned start + notes on fp.job

Tier 2 of the SO->fp.job persistence audit. Four operational metadata
fields mirrored from sale.order:

- x_fc_internal_deadline (Date) - shop's internal target finish date,
  ahead of the customer-facing deadline. Kept separate from
  date_deadline (which scheduling code may adjust).
- x_fc_planned_start_date (Date) - customer-quoted planned start date.
  Kept separate from date_planned_start (Datetime, capacity-adjusted).
- x_fc_internal_note (Text) - shop-internal notes from the order.
- x_fc_external_note (Text) - customer-facing notes, printed on
  traveller / BoL / cert.

All four populate at SO confirm via _fp_auto_create_job, and surface
on sale.order.line as stored related fields for per-line visibility.
fp.job form view gets a Notes group alongside the Customer References
group from Tier 1.

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

fusion_plating/fusion_plating/views/fp_job_views.xml

@@ -41,6 +41,12 @@
                         <field name="x_fc_customer_job_number"/>
                         <field name="x_fc_po_number"/>
                         <field name="x_fc_rush_order"/>
+                        <field name="x_fc_planned_start_date"/>
+                        <field name="x_fc_internal_deadline"/>
+                    </group>
+                    <group name="x_fc_notes" string="Notes">
+                        <field name="x_fc_internal_note" nolabel="1" placeholder="Internal note (not shown to customer)…"/>
+                        <field name="x_fc_external_note" nolabel="1" placeholder="External note (printed on customer paperwork)…"/>
                     </group>
                     <group>
                         <group>