feat(configurator): drop legacy description column after dual-field migration (Sub 2 Task 27)

Removes the `description` field from `fp.sale.description.template` now
that all readers (reports, wizard, sale line) consume the new
`internal_description` + `customer_facing_description` pair.

- Model: drop `description = fields.Text(...)` declaration
- Migration 19.0.9.0.0 Step 6: `ALTER TABLE ... DROP COLUMN IF EXISTS description`
- Template form/search views: swap `description` for the two new fields
- Seed data: write new fields instead of legacy column (dupes old text into both)
- Direct-order wizard: remove `tpl.description` fallback in both onchange handlers

Entech column dropped via Odoo's auto-schema-sync during module upgrade
(migration step is for fresh installs).

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

fusion_plating/fusion_plating_configurator/wizard/fp_direct_order_line.py

@@ -206,15 +206,12 @@ class FpDirectOrderLine(models.TransientModel):
         Customer-facing text lands in `line_description` (ends up on the
         SO line `name`, prints on customer docs). Internal text lands in
         `internal_description` (ends up in x_fc_internal_description on
-        the SO line, prints on WO / traveler only). Falls back to the
-        legacy `description` field when the new dual fields are empty so
-        pre-Sub-2 templates keep working.
+        the SO line, prints on WO / traveler only).
         """
         if self.description_template_id:
             tpl = self.description_template_id
-            customer_text = tpl.customer_facing_description or tpl.description
-            if customer_text:
-                self.line_description = customer_text
+            if tpl.customer_facing_description:
+                self.line_description = tpl.customer_facing_description
             if tpl.internal_description:
                 self.internal_description = tpl.internal_description
 
@@ -235,9 +232,8 @@ class FpDirectOrderLine(models.TransientModel):
 
         def _apply(match):
             self.description_template_id = match.id
-            customer_text = match.customer_facing_description or match.description
-            if customer_text:
-                self.line_description = customer_text
+            if match.customer_facing_description:
+                self.line_description = match.customer_facing_description
             if match.internal_description:
                 self.internal_description = match.internal_description